Correct, the original plan was for City Fall to be an expansion with a fully co-op mode. Then they announced they were ending Shadows and bringing out the two new games.
This campaign has a few red flags for me. The high prices and amount of minis, the high cost of stretch goals, using reviews for the previous game for this one, and no mention of scenarios. It's a shame, I'd been looking forward to the co-op gameplay of City Fall.
I'm not super thrilled with the price either but unfortunately they've got me by the balls for a few reasons:
1.) I know the game is great. Owned Shadows of the Past and my game group loves it. When I caught wind of this Kickstarter way back I sold my Works edition to help fund this.
2.) They know exactly what they did when they divided up what's in these boxes. Even if I wanted to be economical and pick 1 base box, they have the turtles in one and Bebop, Rocksteady, and Shredder in the other!
3.) The stretch goals only being available for the all in is dubious but I see this changing before the campaign ends. There is precedent as the Power Rangers KS did the same mistake but did make stretch goals available for core box pledges after some pressure.
As it stands for me, as a TMNT fan, they only real option is the all-in. Also, they are already dropping hints of a classic pack that may feature characters from the 80's cartoon. Sheesh, my poor wallet :(