I think, "balance gems" should be replaced with something like "never-ending, continuous casting gems," aka, something like the eternity skill, so the skill isn't just for a single gem. Seems like a waste of a slot that way imo
Also, reduce the % from 50 to 25 maybe, since it would affect a larger number of gems that already get a boost. But I like the idea!
Just my 2 cents!