I would enjoy that. I do not like getting preevolutions of old Pokemon or evolutions of old Pokemon. I already trained the Pokemon before, I don't want to find a new item and breed or trade the Pokemon to get a Pokemon I'll only use to fill out the Pokedex. I prefer getting new Pokemon lines.
Problem is that you only get one mega evolution per battle. What if say, in GEN IV, Mamoswine and Magnezone were both released, but you could never use them on the same team. Seems a little silly to me.
I understand my username has an error. Just live with it. However, to see my real signature simply hit alt F4. http://myanimelist.net/mangalist/Xero127