How does Mega Evolution indicate stagnation. If anything, it'd indicate otherwise.
This is also the same thing they did with Black & White's release. They kept much secret. We'll get more plot/game details next month, but the focus of CoroCoro has ALWAYS been new Pokémon.
The large reason of why Pokémon is so popular is the social aspect. The ability to take it with you to battle and trade among many of the other features. This is a core thing as to why Pokémon is popular. Yes, it has online now, but the social aspect is key. The games are developed to be on handhelds, as such, putting them on a home console would lose these core features and would gut the game, with nothing possible on a home console that isn't on a handheld. This is why GameFreak, the developers and people who decide how Pokémon proceeds, have stated that the main series games will forever be on handheld devices.
Basically, it won't work