The Starters need something to compensate for variants. Starters aren't commonly found in the wild, thus would be hard to adapt to certain climates. They won't give standard Pokemon new forms without arguably to most popular getting something in return. I believe they're dropping megas and gonna go this route, with the alternate evos taking on the appearance of the megas. One of Charmanders for example would be his Fire/Dragon X mega, but now its just a standard evolution.

Why? Because it gives the starters that more diversity. Your supposed to share a special bond with them, but when they limit themselves to 3 final forms, and you only have 3 to pick from, they may not be for everbody. This also ensures they remain iconic, as they're base forms will stay the same and won't drift from the classic grass/fire/water system.

Its a brilliant idea. GF have a lot of time to fiddle about with existing mon now that they've done all the models for them. Adding a few appearance tweaks and giving them different stats and moves shouldn't be as much work as creating an entirely new Pokemon.

Its happening guys.