I'd actually like the mega evolutions more if the mega stones weren't held items and there wouldn't be a specific mega item for each mega evolving pokemon.

In my opinion it would be better if every mega evolution would happen with one same item, and they would be very hard to get. I think there should be some major recoil for using the megas, something like this:

>You use a mega stone, the pokemon evolves into mega form
>The mega stone vanishes when you use it
>The mega pokemon could only fight for like 5 turns, then it would faint due to using all of its strength in the megaevolution and battling in its superpowered form.

This way people would really need to think when it's really worth to go on a mega killing rampage and not simply use it on every time possible. My idea is naturally a "beta", since we don't know how overpowered the megas will be.

My other idea was that the mega evolution should be possible only when all the other pokemon have fainted, but that might end up in everyone just killing their own un-megaevolving dudes, just to get that one rape train going, or simply using one pokemon that is able to megaevolve.

What do you think? Are you happy with the current rules (one mega per team) or do you have your own ideas how they could work better?