Also Avenger's Children's Crusade explained that her massive power up was due to Doom using her to tap the "Life-Force" an equal force to the Phoenix Force. Tapping that power due to doom's shenanigans drove her nuts.
So it's all on Doom. And when he stole that power from her, she lost the ability to alter reality willy nilly i think. Still an omega mutant, not Phoenix level anymore.