Welcome to the board, Halx!
It is generally wise to keep any magic user in current role until they have learned all the spells that you want them to learn (not all spells are worth having - like blood to gold
). While the W&W character development is very flexible allowing you to switch roles easily, it can be a bit difficult getting those high level spells if you switch roles too soon. Beyond that, just about anything works!
I personally like having a Rogue in my starting party. There is no Thieves' Guild in Valeia which is the downside but I like rogues anyways!
Have fun and keep us posted on how your game is going!!
Wyv