I can't believe I spent this much time... 
Create Light is fine if you have it, but perhaps a tradition that teaches illusions doesn't teach Create Light. The question remains -- can an illusion illuminate an area, or does it create a "fake picture" that seems to show the area, but is totally fabricated? Also, does casting Illusion Nature 1/Fire (1 or 3 or 5) to get a torch allow for real light, "fake pictures", etc.
Illusions spell example: Hey Look! We're Cats! – Should this spell affect 7 people instead of 6?
Illusion specialist feat: If you cast an illusion with 2+ complex effects and know illusion space and illusion time, do you get a free simple effect from both space and time, or just one?
I was going to defend nonlethal damage until I saw it was the prerogative of Evoke Light. Color me embarrassed!
Ok, on to my ideas on illusions – warning, this will be long, as I am analyzing not only illusion force and illusion nature, but also all of the illusion spell lists. I think with illusion force we have to think outside the box in order neither to make other spell lists obsolete, nor to make illusion force/nature obsolete. Thus I invented a new game mechanic – temporary damage.
Illusion Force: Whether you make a creature, a fireball or a pit, the effect is the same, as far as damage goes. Victim(s) gets one will save for no damage (and one extra one if friends yell “its an illusion”), not a will save each round or “hit”. If the illusion is a creature, the caster can make it auto-“hit” the victims of the illusion up to one time each (although if this is beyond what the creature is capable of, that might give a bonus to the saving throw, or even another saving throw in extreme cases – the illusion should “fit” what the caster is making it do). The "Creature" or “Effect” might seem to do damage by multiple means (or multiple attacks) to a single person, and the victim’s mind would interpret it that way, but the damage would come once, or once/round, in actual fact. The damage would affect anything affected by the illusion.
If the will save is failed, the victim takes temporary damage (see below). If the save is made, the victim won't take damage from that spell. Only creatures in the area of effect can be damaged, even if the illusion creature is meant to be capable of ranged attacks/effects that would go outside the area of effect of the spell. I would suggest that all the MP's of the illusion spell lists (not other spell lists, nor general enhancements) used in this spell be used to calculate damage as if spent on the two regular Evoke enhancements (more damage and/or continuing damage) -- the caster can use these MP's either for a one-time deal, or for continuing damage (for example, paying 4 MP for 1d6 each round over a minute a la Evoke, to reflect damage by a creature in combat, for example. The “free” 1d6 from the evoke cantrip doesn’t count here. Other effects (the gaze of a medusa, etc.) cannot be duplicated.
My new idea: Perhaps we could try a concept of temporary hit point damage (the reverse of temporary hit points)? So the damage would auto-“heal” (assuming the victim is not dead) when the spell duration ceases, or if the victim gets and makes an extra will save, but the damage is real in the meantime (but if a heal spell is cast within the duration of the illusion spell, this damage would be healed last, just as with temporary hit points damage is lost first). The temporary damage could be dispelled from the victim by the Dispel skill, just as spells that grant temporary hit points (like Infuse Nature) can be. Note: the temporary damage cannot be intensified! A successful will save on an intensified spell means the illusion is still seen (or whatever) but does not do damage to the victim.
Instead of the 20/40/60% enhancement for illusion force, I would use the following:
Illusion Force enhancements: Simple (1) Victim(s) takes ½ temporary damage of the corresponding evoke spell (of whatever element the caster chooses (but it should fit the illusion, and no specific elemental side effects beyond ambient can be chosen)) as if points had been spend on evoke equal to the points spent on the illusion lists components, but also as if the victim has made a fort save for that ½ damage (so if there is a benefit from making a fort save, like the mettle ability, she gains that benefit). Note: even for a signature spell, the “element” of damage does not have to be chosen ahead of time. Standard (3) – Victim(s) must make a fort save to take ½ temporary damage – failure results in full temporary damage. Complex (5) – Victim(s), on failing a will save, must make a fort save (vs. full and total MP effect of the entire spell, including all components) or die! (I love my phantasmal killer
). Well ok, actually they only think/sense they are dead/destroyed, so they take full temporary damage, fall prone, go unconscious (if possible), have all senses “turn off” (if they cannot go unconscious), and are out of combat until the spell duration expires (at which point they recover, but are still prone). If the victim succeeds in her fort save, she takes ½ temporary damage.
Note: taking temporary damage might result in real death. If so, the temporary damage does not go away when the spell duration expires, but ambient effects do.
The double save should take the sting out of some of this (note victim does not get the evoke reflex save, nor does the illusionist need to make an evoke ranged attack – the fort save is meant to substitute for these). An evoker would do better (since the damage is permanent, enhancements for specific elements could be chosen, reflex saves tend to be worse, and illusions have that extra will save for no damage at all), but an illusionist gains flexibility in choosing elements. If you think the pseudo-death effect is too great, you could always require the victim to fail the will save (to be affected at all), a fort save (to avoid full damage), and a reflex save (only if the other two fail – this would avoid “death” if made).
Can an illusion with illusion (force) do any damage to objects? I would say likely not, if this stuff requires a will save. Don’t objects always make their will saves? Mind you, the objects might seem to be damaged by the illusion to those who victims who believe the illusion to be real.
Illusion Nature objects are partially real (can support weight, etc.) but cannot do damage. If this means it cannot do damage to objects either, then acid (a weak acid) cannot burn through even a sheet of parchment (come to think of it, neither can “acid” with illusion force, since parchment is an object and so always makes its will save). That is ok. The "stuff" that these objects are made of is simply of a sort that cannot do damage, no matter if you are thrown against it or what. It is a bit springy or something, if it comes to that. For objects, I might recommend a max hardness and hp (that would carry over to the Create spells) of MP (for hardness) and 5xMP (for hit points). But if you don’t limit Create spells in this manner, then you can’t limit Illusion spells in this manner. In that case, at least follow the gp limit (substituting Illusion MP for Create MP on the Create MP list). This is the “green lantern” power, although creators pull it off better. However you determine hardness and hp, the illusion would have the relevant percentage of that hardness and those hit points, making it more easily destroyed. Since it can't do damage, using illusion nature to create an axe would be useless, usually, but one could create an iron (or adamantine) wall to block a passageway, etc. I assume illusion nature would be used if the caster wants a “mount” to carry him (even a flying mount, though that would be risky if someone dispels it). Without illusion nature, such a creature would not actually support weight, etc, but with illusion nature it could support weight according to the strength of the creature (but multiply the load such a creature could normally carry by the %). Here, since Create can make a huge ship, I guess there is no point in putting limits on the creature made by illusion nature, beyond those of the Create spell (on an MP basis). I would not know how to “cost” creatures created with Illusion Nature, but I guess it doesn’t matter once you get to the “any price” range.
Note: unlike with create spells, if the victim does not make a save vs. illusion, the object seems to be real.
Also, the tactile component is needed. What about other aspects? Would an illusory telescope with an illusion nature component enhance distance vision? Would it only work 20-60% as well as a real telescope?
Now onto the other illusion spell lists.
As it stands: The non-intensified sensory illusions (4 cardinal elements, positive elements, negative elements) fool the senses if you fail a save, but are "seen/heard/etc." through if you make the save. So they are fooling the senses and the minds of observers, but the mind can "overrule" the senses (The illusion is like a cover laid over the real world, and a save allows one to peel back that layer of fake world to see the real world underneath, as it were). The intensified sensory illusions fool the senses whether you make or fail the save. You might know that there is a fake layer overlaying the real world, but you can't peel it away.
Note: A dabbler might take illusion earth/air/water/fire to save on spell list expenditures, but a serious illusionist will ignore these and take the 8 positive and negative element illusions (to save on spell point expenditures), since they do the same thing as the cardinal 4, but more cheaply. But there are two cardinals worth getting:
Illusion Death: Changes the aura, but since you use divination spells (actually, the Spellcraft skill) to detect auras, this could count as a "Sensory" effect. Now does using a Spellcraft skill count as "studying or interacting with the illusion", allowing an automatic save attempt? Fitting in with the core rules, the answer seems to be "no". So unless the caster left the spellcraft on with a high duration, and “interacted with/studied" whatever object or creature has the different aura, there is no reason for there to be a saving throw. If there is reason to suspect something ("I know that one of these spears is the Evil one!", the caster could pay for extra duration in spellcraft just to make sure she gets a save vs. illusion, if there is one. I figure this is fair, since using spellcraft on an ordinary illusion of an evil demon will quickly show that there is no evil aura (unless a clever illusionist uses illusion death to put one there), which would indicate something weird enough to warrant a saving throw, if one knows that there should be an evil aura.
Illusion Life: This must take a piece out of the mage's own consciousness (or create a tiny duplicate of a part of the mage's consciousness), and implant it in the illusion. How else could the complex version act in the way that the mage would want it to, even if the mage were miles away? It must have awareness of its environment, of a sort, if not an independent will. A "guard" has to see/hear to be able to respond to questions intelligently, and it has to have memory to believably respond to a series of questions intelligently. This consciousness does not return to the mage and dies with the illusion, however, so the mage can't use a "spy" to get free memories. However, I see no reason why the spy could not be later found by the mage (before the duration expires) and report to her (verbally or in writing), since that is just answering more questions about what it saw and heard and remembers. The mage is unharmed by this process of losing a piece of consciousness. Effectively, as far as getting a spy (or anything else, come to that) a Summon spell could do the same thing.
One question: if the mage changes his mind on how he wanted the illusion (with complex illusion life) to act, after the illusion is created, I assume that he can spend time changing it, as he would a cantrip, if he is in range. If he is out of range, I assume the illusion runs on the "old program".
This is a nasty one to cast on an opponent to make him seem like the worst enemy of his buddies! The actions of that “enemy” would be interpreted in the worst possible light ("He is not attacking us! Yet listen to how he taunts us! He is either weak and bluffing, or overconfident.") Especially when combined with the appropriate intensifying effects (even if the buddies know it is an illusion, they can't determine who is under the "overlay" of the "worst enemy"). Actually, this works even better if you cast it on two buddies that are your enemies, to make them see each other as their main opponent. Maybe a signature spell “Let’s you and him fight”.
Now on to the strange ones:
Illusion Space/Time: This is a weird overlay on the real world, but still an overlay. Interestingly, it is local in a way that other illusions are not (an illusion of a dragon can be seen from outside of its area of effect, but time and space are only perceived to be distorted from within the area of effect). You both affect an area (a point in space with a radius, one would assume), and target creatures in that area (and those that enter the area). The creatures then perceive a distorted view of that area, spatially or temporally. The "any or all distances" for illusion space assumes that if one affects some distances but not others, the victim's mind will "draw a map" to make sense of the information it is getting. (What would the discerning enhancement do here? For time, nothing I can see beyond affecting only certain people in the area of effect. For space, if someone left the area and looked back, it would still look distorted? Maybe Discerning enhancement only lets you choose between friends and foes (and would mean latecomers don’t get affected at all, but doesn’t “stick” with victims that leave the area of effect)).
I assume that all of the above, on the "overlay" theory, can affect creatures that have the relevant senses, but are immune to mind-affecting effects. Just as mindless undead can be affected by charm spell lists, for instance.
