>>27475594This is my theory.
You will be able to find mega stones throughout the game a la ORAS.
The main focus of SM will be stones. Mega Evolution will not be emphasized.
You will be given a mega evolution bracelet SM postgame.
You will only be able to wear one bracelet at a time. Thus, during pokemon battles, you will have to choose between using a mega evolution or using a "burst" attack. You will not be able to use both.
Lastly, I do not think there will be new mega evolutions, but it is a possibility. At the least, we will see the known mega stones return.