I have very, very little faith that the spin-off will be very interesting...and they are risking burning people out on the franchise as a whole, which would be a disastrous mistake for AMC.
I would have preferred Frank Darabont's original idea. I think between season 1 and 2 he was going to do a tv movie about the fall of Atlanta, ending with the soldiers in the tank that Rick briefly found himself in. I think it might have been cool to have something like a limited series following Sasha and Tyrese's group between seasons, and then when the next season is in swing, they find their way to Rick's group. So, the mini-series/tv movie idea would be such that it wasn't involving the main cast, but it would help fill out the world for those who want to know more.