As most of us we know that in the 6th generation of the pokemon games they are introducing us to a new game mechanic, Mega Evolution. But to me the term "Evolution" doesn't fit very well with what I've grown to know.

An Evolution, to me, is the process in which due to some circumstance (whether it is obtaining a certain level, using an evolution stone, evolution via trade, happiness evolutions, ect) that it results in a permanent transformation that brings greater power than what they could have obtained if they haven't changed.
Now the new Mega Evolution doesn't fit this since it isn't a permanent change, its an in-battle mechanic that will wear off once the battle is over.

How I would have done the Mega Evolution is have the Mega Stone as a special Held Item. Once the requirements for the pokemon to evolve are met (level, stone, happiness, trade, ect) is that instead of evolving into their normal evolution form, that they instead evolve into their new Mega form.
(Example: Bulbasaur -> lv16 -> Ivysaur -> lv32+holding Mega Stone -> Mega Venasaur
Absol ->Happy+holding Mega Stone -> Mega Absol)

If you don't agree it's alright, this is just what I think, I'm just venting.