I have a con:
The way 'forme' is spelled. It's not even a word! D:
Pros:
Spin Trade
Guests (Joanne, Jasmine, etc.) in Master Rank Contests
New Forms (Shaymin Giritina, Rotom, etc.)
Cons:
Some Pokemon removed from places.
No Underground Wi-Fi (Picture for a moment how much of a frenzy that would be, though.)