Still, a 14 level magic user can cast... how many... 50 spells/day? More? Try to navigate in a real time combat enviroment through a list of 50/60 spells then tell me if it's user friendly
I can only trust you've never played either Neverwinter Nights game, then? In all fairness, you either need to know what you're up against (sending an invisible familiar to scout, for example) or be very good at improvisational thinking in order to get your spells off as desired, but it can be done. The actual issue I came across wasn't picking spells off of a list (NWN uses Quickslots to mitigate this), but rather aiming my spells in a timely fashion to hit the optimal number of opponents that they would hit in a turn-based environment such as tabletop.

Of course, this was hindered by my own regrettably poor aiming skills, but luckily, they make bunches of wonderful spells which are single target or self-aiming, so I could generally manage to struggle through. Although I still generally played some kind of melee character, just because Knockdown was such a ridiculous weapon