That's exactly what I'm thinking of. Parse things out and draw solid lines between who gets what.
When I have seen this tried in actual play it tended to go to one of two unsatisfactory results -
1 everybody had and used the "same spells as far as results but the cosmetics were different leading to essentially a devaluing of the six choice itself.
My +3 AC spell is from conjured swarms of animals or insects interesting and making it harder to get clear shot. Your is a force shield. The other guy's is an illusion fuzzy thing.
My fireball is a fireball but the summoner has an insect stinger ball and the charmer has a painball etc all do 8d6 in 20'r etc.
2 There are actual hard core meaningful differences between them but that results in some being reduced to niche charscters better served up as NPCs because they dont cover as many of the necessary elements as several others (necessary from campaign "what we do" perspective.)
You guys manage to break that streak and concoct ye olde "we found the sweet spot" where it all stays in a happy middle ground of a meaningful choice vs breaking cuts vs cosmetic only - that is great.
For me, I think they had the right idea with fewer penalties, cuts and denials (removing the wizard specialist opposite schools) but instead they lost out by not giving you **more benefits** to your specialty.
I would like to see say a sub-class specific short rest arcane recovery that only applies to your specialty. More incentive in play to use your specialty to solve the problem rather than just whatever is best.
"When you cast a spell of abdc school of 1st or higher, check off add 1 to your arcane recovery total. When you take that arcane recovery, regain the higher number of levels of slots."
Could also give extra prep slots equal to int only for school abcd spells.
In general I find incentivizing the focus better than cutting out the other option as far as "winds up successful dedign and play".
But again, maybe you got the just right goldilocks sweet spot that shows the others wrong.