I know that in the next season mionions will be changed and, argeuably, more important. However, they will still stay the same on both sides (not including mega minions, baron buff and that one item no one buys). I personally think there should be more induviduallity and gameplay regarding minions.
A good example in the correct ( or what i want it to be) direction would be the minigame BMB, or Black Market Brawlers ( it was during the Gangplank event ). The combinations and strategys you could pull off were increadable. Although a little too crazy, the gameplay was exiting.
Something you could do is making a new tab in the market where you can upgrade a minion. At the start you´d either get controll over a caster or warrior, which would different types of uprages and the more you upragde /make it better, the more gold it gives when killed.
Either way, those were my thoughts about a possible improvment on the game. Argue against me