Mercurius said:
The 4E multiclass rules handle this quite nicely.
It's got problems with feat taxing, but I think it's got a good core of an idea.
I don't like the idea of a thief always having a chance to cure light wounds unless trained, however.
Well, that's cart-before-the-horse material. You define a group of things that everyone can do, and put it in one silo, and you define a group of things that only special training can let you do, and you put it in a different silo. The stuff everyone can do, everyone can do (even with varying rates of success). The stuff only special folks can do, only special folks can do (even if they might not always do it well).
Skills do this with things you can do untrained (e.g.: general rules for climbing and the like) and things you can only do trained (e.g.: taking an Atheltics skill power in 4e).
"Healing" is defined as something anyone can do a bit of. Anyone can make a Heal check to perform some first aid. Anyone can use a Potion of Healing.
Using "Cure Light Wounds" is something that is a specific ability. Only those with that ability can do it. It is entirely outside the scope of other healing options. It isn't just "harder to do," it is a brand new element.
The question then becomes, where do you put down the walls of those silos?
What's crucial here to me is that the silos aren't defined by the
difficulty of doing the thing. It's not that Cure Light Wounds is some extra-hard application of the Heal skill. It's an entirely different thing that completely bypasses the Heal skill entirely and uses entirely different rules.
So balancing on a tightrope during an earthquake is not material for this kind of silo, to me. It's hard, but it's still ultimately just balancing -- something anyone should have a chance to do.
However, perhaps declaring automatic success while balancing on a tightrope IS a kind of special ability, entirely bypassing the balancing skill, and doing something using entirely different rules.
So "you must be THIS trained to even attempt to balance during difficult conditions" is vastly unappealing to me, since anyone should be able to try and balance, just as anyone can try to perform first aid. But I have no problem with "If you are trained in Acrobatics, you can take THIS special ability that lets you auto-succeed on a balancing check."
That means Bubba the Serf has a 5% chance of hitting Orcus with his broken pitchfork (although damaging him is another thing, but you get my drift).
Well, if Bubbba the Serf was a PC, and, thus, a special unique snowflake in the world, that would make a certain amount of heroic sense!
I don't really dig the idea that Bubba has a 5% chance of casting meteor swarm if he says "abracadabra" and waves his dirty paws around. Certain capacities require training, especially the esoteric arts.
Is magic something anyone has a chance to do, or is each spell a unique, discrete trick you learn? This is an answer that varies from campaign to campaign. If magic is something anyone can do by reading a book (such as perhaps in the Lovecraft-verse), then anyone should be able to do it, and even have a chance of doing it really well. If each spell is a more narrow, specialized, trustworthy ability, then it would make sense to require possession of that ability.
To give another example, let's take tripping.
In 3e, tripping was something anyone could do. You could be better or worse at it, but anyone can do it. This makes logical sense, since any goofus can try to knock down another goofus, and you can imagine that a trained individual would be even better at it.
In 4e, tripping is something that is a specific, discrete trick, used with a special, unique power, that no one who doesn't possess one of those powers can attempt to do, ever. It's arguably better balanced, but it is also arguably logic-breaking, since it doesn't make logical sense that my wizard can't just have some chance to knock some goofus's legs out from under him.
If your skill is something that anyone should be able to at least try to do (such as balancing), there shouldn't be an artificial limit to possible success. If your skill is something that is a more discrete ability (such as spellcasting in most D&D games), it shouldn't be part of the skill system at all.
Difficulty class shouldn't be set by specialization, IMO. If anyone could try to do it, anyone should be able to try to do it.