Only a commentary on 3e rules:
"To become an abjurer, a wizard must select her prohibited school or schools from the following choices: (1) either Conjuration, Enchantment, Evocation, Illusion, or Transmutation; or (2) both Divination and Necromancy."
- Players Handbook
The spell restrictions on IWD2 are too severe, comparing tho the P&P 3e Rules.
The fixed restrictions usualy different and you lose too much.
For exemple, to become a Diviner in P&P 3e, the weakest specialization (not the worst), a wizard must select any single school as a prohibited school, in IWD2 the prohibited school for diviner is Conjuration, one of the most powerful.