I think that we should have Balance Prisms. This doesn't mean that Kingsisle needs to add a "Chaos School" ... The prism could transfer to ,,,,,or . It could pick the school randomly like spectral blast, and speaking of that, sure, we've been given spells like Spectral blast, Hydra or Chimera, or even Gaze of Fate now to do damage to balance bosses and enemies, But in worlds like Khrysalis, the spells are just simply weaker than your typical balance school spells like Sabertooth or King Artorius etc. And we should be able to use those to kill Balance bosses, it'd be great to use Ra to kill balance minions. You could get a quest from Alhazred at around maybe level 20 to get the quest, if you're higher than 20 then you can still get the quest, and the mass prism can be trained from Cassie the Unicorn like every other mass prism.
Been suggested before and isn't needed. There's no balance shield, that is one of Balance's advantages. If you make a prism it would follow that you should also have all the shields against Balance that every other school has to deal with. As for killing Balance minions, I used Ra for that all the way through Khrysalis even before getting Shrike.