An increased crit chance isn't the only thing molten armor is giving you. Perhaps its the only part of molten armor you care about... but I doubt Blizzard is going to totally base their balancing on you.Originally Posted by Blizzro
In simple terms, inner fire gives some increased protection and some increased spell effect.
In simple terms, molten armor gives some increased protection, some increased spell effect, and the game's best damage shield.
However, inner fire has 1/3 the duration of molten armor, and it is limited by charges.
When you consider talents, things stay about even for molten armor being as big of an impact ability on mages as inner fire is for priests, since impact works amazingly well with molten armor, though it has little use in pve... while the disc talent for inner fire is also situationally worth the 3 points.
However, molten armor's damage shield component scales with spell power and critical rating. Inner fire gives flat bonuses.
Furthermore, the glyph for molten armor actually makes it more powerful... adding to the "increased spell effect" I mentioned above. The glyph for inner fire, however, does not make it more powerful... only less annoying to keep up.