Rystil Arden said:
Actually it doesn't balance at a Move Action--because you can then Quicken it and get the regular Wraithstrike back as a level 6 spell, and it is still overpowered at that level.
This I would disagree with. Wraithstrike is strong but not so strong that it is better than a 6th level spell. It gives a huge bonus to hit because it is a touch attack.
However, 6th level makes some things change:
1) Low level dips can no longer acquire it. You need a focused Fighter/mage to acquire this spell requiring 11 levels of casting. This is becoming a good boost for an Eldritch Knight (at least 13th level for this class combination assuming it is based on wizard).
At 13th level the Wizard is casting Finger of Death, Reverse Gravity and Forcecage. Heck, even distintegrate is likely to do as much damage as a full attack action.
2) One of the nice things about Wraithstrike is that it comes out of spells that are rarely used but remains highly effective at high levels. Unenhanced second level spells are rarely effective uses of an action at 10th level. Wrathstrike was a notable exception to this rule.
3) Other metamagic competes. Using of Energy Substitution (to avoid energy resistence) and Empower on Scorching Ray is a 5th level spell. The 6th level equivalent is Maximize or Twin. Doing 24d6 (twinned) damage as a ranged touch attack at 50 feet plus (by this level) is generally easier to pull off than a full attack that requires getting close and is less investment than a charge based Wraithstrike.
4) Adding this spell to other lists (for example, via Extra Spell should you beleive that works) is no longer a complete no brainer for Paladins and Rangers. Only full casters with Quicken spell as a feat will see this as a potentially worthwhile investment.
It is still a decent use of a 6th level spell. But, now, it appears that there are choices that might be equally good or there is a requirement for a lot of investment in a particular strategy. I don't mind if careful investment can provide good options for a character. In particular, once multiple feats start to make sense then I think that the character is picking an option. That is good.
Once there is choice the spell starts to balance.