Mega Evolotions

The mega good bad and hard!
This is weird. I'm pondering over Mega evolotions. For one My favorite original pokemon charmander has an evolotion with a mega evolotion and it is cute! Mega Absol is pretty. The problem is will they be with trainers? I mean it's not perminent but if they can use them it might make it hard. Not trying to give ideas but, I really don't want the elite four to have them. Man that would be Awful! Other wise I like mega evolotions!