C'mon Joe, we know you love Pokemon and everything, but you can't really say this with a straight face. Customization is important to many people (me included; even though it's not essential I loved it in XY) and it was cut in ORAS. The excuse that it was a remake doesn't make sense, because mega evolutions, Super Training and Amie remained there, and it wasn't available in the GBA games.
If we go through Sun & Moon and it's gone, then I'll concede that it is cut. However, for ORAS it does have a little sense that it wasn't included to differentiate
Nope. I just thought it was Ash fusing with Greninja.
And I don't like Mega Evolution because it seems like a cheap way of making Pokémon relevant without actually giving them an evolution. "Oh, we want more Charizard but can't make him evolve any more? MEGA EVOLUTION!" "Oh, we want to do something with Aerodactyl but don't want to give it an evolution to make it worth using? MEGA EVOLUTION!" "Mewtwo is cool but we can't go having a Mewthree... MEGA EVOLUTION!".
And then it's like, here, have a Pokémon that is basically as strong as a legendary but you don't feel bad for using it.
Synchro appears to just be like Mega Evolution (like how Primal Reversion is similar), except it only appears to happen in a pinch, not activated. We'll see how it's implemented.
And yes, that is part of the concept behind Megas. There was a power creep but, due to the Eviolite item, they couldn't really add more Pokémon to the evolution chain (they like to keep things consistent, so if something existed in the past game, it can't really be used to activate new things, which is why Moon Stone doesn't evolve Eevee into Umbreon, Leaf Stone doesn't evolve Eevee into Leafeon etc., there's only one example of this that doesn't hold up though, and that's Lickitung's evolution method).
Mega Evolution is actually a fantastic mechanic in competitive battles. It really changes up how you battle.