Are the home team going to be choosing the pitch? If so, which I think we should do, home and away would be great fun. Durham have a pace bowling team whereas others have very good spinners, so home advantage could be crucial. Teams might have to employ a second reserve though, because 4 months is a long time, and plenty can happen in people's personal life.
I don't have any issues with a 4 month, 16 game tournament though. Finishing after 8 games might be a bit of an anticlimax, whereas the 15 man squad will be properly used with 16 games.