Hi Hekireky,
We absolutely would like to see mages with varying spell point pools for spellbook construction. One of the issues we struggled with is how you deal with this in custom scenarios where players mutually agree beforehand to build spellbooks with an alternate number of spell points. If players decide to play by a 'house rule' and use, say, 125% of the prescribed spell points, then each mage would have 150 spell points to spend. However, if they have different totals, the scaling has changed, and mages that naturally have more or fewer spell points will receive more or less additional spells, respectively. If players decide to use a flat spell point modification, such as +20 spells for each mage, it still isn't entirely fair because going from 80 points to 100 points is of greater benefit than growing from 140 to 160. This last issue also presents itself in our ideas for 'campaign modes', where a mage can advance and improve over the course of a campaign (perhaps lasting a few weeks), and acquire bonus spell points to add to their pool.
These issues are minor though and not part of the core game. I would definitely expect to see mages with a different number of spell points in the future - though it is unlikely to deviate far from 120 since this value has been fine-tuned over years of playtesting.
On a side note, Klaxas is right about the "Arch-Mages". These are being planned for future expansions that allow unconventional arena scenarios that support 2v1 or 3v1 play. Though I am unable to say at this time how far down the road to expect something such as this.