Playing Pool Of Radiance got me learning the ins and outs of 2nd edition AD&D and I came to the realization today that I prefer games with a magic points or mana system. Probably because I grew up with JRPGs which exclusively deal with MP over spell slots. Don't get me wrong, D&D is great, but it's such a pain when you get into battle and you realize you forgot to memorize Detect Magic and now you have a bunch of potential good loot.
Thaumatology. And nothing says you have to spend FP to cast spells. It is suggested as a possible default way of doing things, and GMs will often make you do that, but it's not a hard rule.