I wonder how much of the difficulty you experienced was due to the the combination of horrendous organizational choices of the GURPS Magic book, and the sheer volume of available spells.We created our own characters the first time I played GURPS. To make matters worse, I am caster obsessed and insisted on making a caster. I realize that was my choice but it was what I wanted to play. The character creation process took many, many hours and gave me a headache. ... It is difficult for me to offer specific criticisms because it was a long time ago (2009) and I never understood the game, lol.
Like, don't have both a complex system of prerequisites for magic spells AND a non-alphabetical organization of those spells.
SJG learned from that mistake and at least in DFRPG, Dungeon Fantasy: Spells has all the spells in each college listed alphabetically, and it helps a lot, but wizards/clerics/druids/bards are still one character type that I cannot generally create from memory. I need to use the books and/or a web app (Dungeon Fantasy Spell Prereqs) or sometimes both.
Anyway, my point is that the gameplay is pretty simple and even the rules aren't too bad, but the design of the book may have made chargen unnecessarily complex in this case.