I don't know how this works in England, but in Spain, small teams (even first division teams) can have a lot of changes each season (end of contracts specially, and selling players) . Losing ten or more players it is not a surprise to anybody.
So, let's say that we maintain our players. Which won't happen, though. Then we need a keeper (we sold Becerra (u19 Spain European champion) and we are still suffering it).
Our star is clearly Pere Pons. It's a player that can and should have been playing in first division but stayed loyal in the club he has been since he was a kid. You will see it next season when he gets more exposure in first division.
Maffeo has been our best defender (we haven't defended too well, at the start of the season we have at some point received the most goals of the entire division. That means we need defenders like him, please) , and arguably our second best player. Kudos to him. I hope we manage to keep him next year.
I will also have a shout out to Longo, as his goals haven been important. We are the team that has scored the most goals in second division.
Also comment that it is quite cheap to watch a match (specially pre 2015). One season for less than 250€ is quite nice. I hope the don't rise much the price.
Edit: i really can't tell what players would be good, as I don't watch city that much. The champions league fixtures, and odd match here and there. You can tell me what promising players could do well in first division level.