Lizard said:
More seriously, I think this is another example of how constrained the 'design space' of 4e is getting, and how fewer and fewer truly different effects/concepts/etc can be wedged into it. It looks like almost anything interesting is being dumped into a huge bin labelled 'rituals'; virtually all spells/powers/exploits are simplistic variations on a few themes, with complex concepts like 'mirror image' becoming just a special effect for 'ablative AC buff', for example. You can no longer bring down a flying mage with dispel magic (always fun!), remove a ward/sigil, turn off that annoying magic sword, etc.
Setting aside the whole "we're already sure there's no way to remove a ward?" issue, this design space constraint isn't something I'm seeing. With keyword-based spell interactions, I can create entire new spell schools just by plugging a group of spells into the keyword system.
For example, say I want to make a school of blood wizardry for some villains. Some will be fully statted, others will just have a few relevant spells. I create a new "Blood" keyword, and define it thus; "Using this power subtracts its level in hit points from either the caster or a blood cultist within 10 squares, with no hit roll needed. Cultists or casters dropped below 1 hit point become unconscious or dead as normal after the spell is cast. If the caster draws from a cultist, gain the spell's level in healing. Blood powers gain +2 to all hit rolls and apply a -1 penalty to all saving throws versus their effects." Then I slap it on a bunch of book-standard wizard powers and dole them out to villains, describing the spell effects with suitably gory special effects.
I've just added a brand-new factor to fights just by adding a user-defined keyword. Now PCs have an additional incentive to take out the blood cultists before they go after the wizard, as each spell drawn from a minion heals the caster. They _can_ try to burn down the caster first, but that will provoke him to throw his biggest spells first for the healing, creating a very gory encounter... which is precisely what I want.
If it's completely new spell effects you're looking for, I can't see how they're harder to do in this model. I can think of a half-dozen new mechanics off the bat:
Arcane Turbulence: Roll Int vs Will against one enemy. On a hit, all Arcane sustain minor/move/standard powers require two additional sustaining actions of the same type. On a miss, they require one additional sustaining action. A saving throw ends either effect.
Chord of Thaumic Unity: Cast on one willing ally trained in the Arcane skill. Ally gives up one type of action, standard/move/minor. You gain that action for use only to sustain an Arcane power. Spell lasts for one encounter or until the ally ends it as a free action.
Anathemic Backlash: Immediate reaction. When someone uses a Divine power within range, roll an Int vs. Will attack. If successful, the power takes a -4 to hit, grants +2 on saving throws, and does 1 point of damage per level to the power's caster.
Flux Point State: Immediate reaction. Partially transform into arcane energy for one turn. Martial powers suffer -4 to hit the caster, while Arcane powers gain +2. Cannot move except through power use; immune to forced movement.
Zone of Twisted Space: Zone power. Move sustain. Anyone ending up within the zone at the end of their turn may be shifted one square by the caster's discretion.
Shockwave Rider: Immediate reaction. When struck by a Blast effect, you may roll Int vs. Reflex against the caster. On a success, you subtract your level from the damage, take no ongoing effects, and are pushed to a square just outside the blast area chosen by you. On a failure, you take normal damage and are pushed as above.
...and that's just with fifteen minutes of contemplation. I find 4e's system more conducive to creativity because it has an explicit and developed framework for interactions between powers.