I think they're screwed either way. If they had used new characters, people would complaining asking where Columbus, Wichita and Tallahassee are, and that it's not Zombieland without them.
Recasting was probably the best bet.. and if it goes to series, either these actors grow into the roles. or they don't.
I disagree. I do not think many would of had a problem with new characters. The appeal of the movie was the chemistry of the cast members. Without them I am not sure what defines the characters.
I am going to be surprised to see if this lasts long. People wanted a sequel with the same cast. I do not think the novelty can sustain a series.