>>39160058Given that Mega Evolutions are my favorite mechanic I wouldn't change too much, but I'd probably do the following things:
-Charizard and Mewtwo both only get the Y evolution (Charizard's Y form was revealed along with the other two starters form and looks more like the next logical step in Charizard's evolution line while Mewtwo-Y brings Mewtwo closer to Mew)
-If a pokemon's regular ability would serve the mega better, it can keep that ability instead (for example, M-Houndoom can have Flash Fire, M-Steelix gets Sheer Force and M-Audino can get Regenerator)
-Bring down Megagross and Megamence to the levels of the other pseudo legends (the -ate abilities give no damage buff, and Megagross keeps Clear Body)
-Rework Mega-Banette to make the most of it's design and redistribute it's attack amongst it's defenses so it can properly use prankster
-Make it so Mega Kang could never have learned Power-Up Punch in the first place, but let it keep Parental Bond unnerfed to compensate (re-nerf if it proves too strong still)
-Remove Perish Song from Gengar's movepool, but let it keep shadow tag even though I hate the damn thing because it's a fitting ability
-Make a few more megas, such as Flygon, Milotic, and more specifically a few for gens 4 and 5 such as Golurk
-Focus on tweaking and balancing Mega-Evolutions instead of adding new gimmicks to make them more balanced in comp play each gen
-Offer a battle spot mode that bans them outright so people who hate them don't need to bother with them
-Add a handful (like, 5 or less) each new gen, depending on who needs them the most
I know it's probably still broken but I think I fixed most things.
I'd also add Mega Clefable because I was hoping it'd get a mega back in gen 6 before it turned out not to need one, but in a OU where M-Gengar or M-Gross could be legal it'd be a fun idea. 