I do think the energy recharge spell can be useful, I often use it when transitioning phases in boss fights, or toward the end of battles with mobs to recoup MP if they’re almost dead. Warrant is also a source of keen more than anything, but the issue is it does hurt purge and purge is probably too strong to justify prioritizing keen stacks. Anyway, you’re not wrong, though, i do think there are spells you just don’t end up using and that is a problem, but I’d also argue that for the majority of spell schools you do use all three spells, or at least could use all three in certain conditions. I think Holy Magic and Sky Magic are sort of outliers in having spells that aren’t commonly used.