ability to play as pure magic user would rock!

[Ryastar]

I think the thing here is that the spells you named - the ones that don't scale as much with int, or at all - are the spells that are meant more for warriors and paladins, whose intellect is far lower. I agree that it is weird that those spells don't seem to increase duration with int, despite the game saying that every 15 pts adds +1 to duration, i think it might be a glitch or oversight. However, many more spells DO scale with intellect, and i believe that those are the spells that are meant more for mages. Damage spells are the perfect example of this - the more int, there more damage, each point of int adding +10% to the damage and every 7 a bonus 10%. These are not the perfect solution, as it is impossible to only use damage spells, and win. You do also need troops to deal with the more annoying enemies. THIS IS NOT TO SAY THAT DAMAGE SPELLS ARE USELESS, just not the perfect solution.