I'd like to see Jessica Jones get a second solo season as it'd be kind of sad to see Marvel's first female lead superhero series/second Marvel female led series get merged with Luke Cage and Iron Fist. I'm sure the tone will be different between the 3 of the shows.
If they are good and can remain good I'd rather not see any of them merged. If they aren't great but just ok than they could be saved by merging them. I know Heroes for Hire partnership is popular but the IF mythos and the Cage-Jones relationship are the bigger draws for me, so if anything has to be merged I'd rather it was Cage and Jones.