>>21179589They add what pokemon needed: a new addition to gameplay.
Mega evolutions allow you to carry essentially 6.5 pokemon in your party. The megas each have their own unique niche and are usually given to under estimated pokemon (with the exception of stuff like Charizard/Tyranitar, etc.)
The last real change we had was the physical/special split of gen 4. The mega evolutions are kind of like a "secret weapon" for your teams.
As an added bonus they make kids like you accuse others of being children.
