So your friend had to spend points in strength, const, speed, AND int to get some small level of viability. Mages only need int, and would definitely be able to do whatever your friend does more effectively.
Nothing needs anything or only anything. Mages could only be given Int, but I wouldn't say that is idea, there are reasons for Cons/Speed and Perception to have more AP turn to turn. Fighters could only be given Str.
This game imo playing the first chapter is fairly easy once you understand the mechanics, imo we are arguing what class makes the game the easiest. No doubt mages have a ton of skills/options on hand.
