I know it's not as simple as "do a guide", but the exp system could be the new target for a revamp maybe?
I mean, most of the problems occur based on exp discrepancy and it feels natural to address this situation. Enemy jungle camps giving less exp, even less exp to laners that last hit camps, I don't know, just throwing some thoughts.
I agree the exp system is likely a good place to look, exp is a super super fickle mechanic so I think finding the right balance there is tough, but worth looking into.