First off, I’ve been playing D3 since 2015 or 2014 and i LOVE this game, but i came up with an idea of how they can improve the legendary gem system, here are a couple of possible things they could do.
Make it so the gems when at level 0 are completely useless (e.g. bane of the
powerful starts with 0 seconds at lvl 0, and every rank increases the time of BoTP
by 1 second.)
Make different gems e.g. BoTP have two legendary abilities for it, not only could
BoTP have the lasting effect of 20% increased damage or whatnot, but instead,
each rank (after level 0) the increased damage would be increased by 1%, up to 100%, after it has hit 100% it would stop increasing but you could still keep ranking it up to increase the amount of seconds you have 100% increased damage for.
These are only two examples, but i believe that this could actually increase the “grindyness” of this amazing game, and that it could actually make the game better. if you were bothered to read this, thank you, and i do not mind if you yell at me in the replies for it being a bad idea, remember this is only my opinion of how i think we could improve this game.