Currently, there are many spells you can learn from many schools, but most of them are frankly useless for every school in every situation.
There's no reason to use another school for damage: the gear and pips don't justify it. There are some useful utility spells that everyone picks up (tower shield, feint, spirit blade, etc), but no one wants the damage spells because they'd be twice as expensive to cast and you wouldn't even even get stat bonuses for them.
This leaves a few possible solutions:
1. Make it so the trainers offer all of the utility spells that each school has: There's a few useful ones, but not everything. Utility spells are genuinely useful and worth training, that's why everyone uses sun and star spells.
2. Make top tier gear with split schools: I recall Celestia kind of had something like this. If you could do damage with another school as well as your own, it may be viable to train other schools. You could even just give mastery amulets really good stats for that school to get you in a reasonable place.
3. Make it so you can use a version of that spell in your school: there are spells out there that are different flavors of the same thing like deadly Minotaur. I think training a version like that would make damage spells viable. Treasure cards would still be confined by power pips, but committing training points would lift that burden. This would also let a lot of people diversify their decks a lot, and everyone would get tons of shiny new spells that they can use (one of my favorite parts of w101.) Even if permanent school conversions were a (reasonably) craftable thing, I think it would be a big improvement.
What are everyone's thoughts on this? Split schools being viable would make schools lose a lot of their identity, but the deck variety would skyrocket.
