Something to consider about mage learning points…
You can increase your mana right from the first level up and not invest any exp' in either melee or bow skills, just mana increase. The axe and the ring found freely in the game will get you to chapter four easily without melee or bow skill increases. A further magic scroll found in the game will let you destroy a magical golum and retrieve a heart which will let you destroy most beasts. In sequential increments further rings and amulets will boost your skills to enable use of the other weapons and gain the other hearts. You can, if you wish, even clear the game world of all living things. all undead, all orcs, swamp sharks etc' with magic only - totally dependant and subject to the quest links and storyline triggers via the chapter changes. This means getting to chapter four with just magic increases. At Chapter four when losing the golums hearts to Xardas, you will have much magical power of you own.
So why even bother about distribution of exp into combat skills at all?
When you become a mage and quickly reach the higher circles (because you have stored your exp') you will further realise that there is no need to invest in any weapon skills at all right up to the game ending and completion as a pure mage.
Edit:
To play as a purest possible form of mage in gothic using no combat or melee weapons at all would mean getting the ice golums heart at the game start.