Soooooo, did I miss the memo? why are almost all my spells maxing at 50 mana preps now? So is this like a nerf, am I only hitting at half power now?

All the attack spells I know besides db bg and fb cap at 50 mana.

Debil + TM = 50 mana cap. That's a buff. You get 100% power at 50% mana.