How to save Mike & Molly
1. kill off Molly (car accident, heart attack whatever).
2. Have Carl and Victoria get engaged and he moves in the house with her so we have reason to keep the core cast.
3. Mike moves into a better apt with Sam and we see how Mike moves on with dating and a new relationship with another woman.
4. Rename the show Mike At Large or Mike @ Large
Ideally it would have been better for the show to have gone with Molly being pregnant at the end of season 3 because a grandchild for Joyce and niece or nephew for Victoria would have been a better link the core cast and the house as Mike would let them babysit often but this is the best I can think under the current circumstances.