I mained SCH since I started FFXIV then I switched to AST and I've never looked back. Ive only ever ran into 1 or 2 occasions where I've had to throw myself a hi-elixer. It takes quite a bit of patience to get into the groove of playing AST. I understand fully how new AST have MP issues.

It comes I think from playing SCH, when your MP pot felt endless so you could do what you want, when you want. With AST it's all a bit more reserved and casting at the absolute right moments. Precision is key.