we're going to have an issue of too many superstars next season and some will need to eventually go...
---------suarez----griezmann
---------------messi
Coutinho-----Busquets------Rakitic
Alba---Umtiti-------Pique-------roberto
--------------ter Stegen
subs:
---------------Munir/Paco
-----------------Alena
Iniesta----Arthur---Paulinho-----Dembele
Digne----Verm--------Mina---------Semedo
----------------Jasper
that's a 22 squad list that is going to be very similar to real madrid's 16/17 season where players will complain with lack of starting minutes and some will have to be sold the season after the next... but we'll have a stacked team and rotations would never be an issue.
if we sell Rafinha / Gomes / D. Suarez / Paco(or munir)
and keep Samper + B team keeper we'll have a solid 24 man squad with an extra coming from B team if needed... this are things from FIFA or football manager and idk if valverde would be able to handle so many players demanding minutes
Don't really see many players from that 2nd lineup to complain a lot about their minutes like Morata, James, Isco, Asensio,.... in Madrid last season.
Dembele will probably be the only one who will expect to start and Valverde's toughest job will be how to keep all 5 "big ones" happy. Whether by integrating all of them in same lineup which I doubt is possible without risking defensive stability of the team or by finding a way to rotate them. Except Suarez they are all versatile and could play in 2-3 different positions so that's a good thing. Maybe Suarez and Messi will finally accept they need more rest, maybe Dembele will accept not to be a guaranteed starter right away in his first true full season after this one was mostly washed away by injuries. We don't know if some of those things will happen but I believe all of them are team-first players and EV also seems to get along well with his players so maybe he could manage them (for more than just one season).
Semedo could be the other one to become unhappy but until he proves he deserves to be a starter nothing should happen. I think he'll get another year but if he can't take a starter spot away from Roberto next season then the club alone will probably be the one to think about selling him before he could express unhappiness about playing time.
Don't really see much problems with other players. Arthur will come only in January and even if he comes in summer he'll need 6, 12 or maybe 18 months to adapt. Alena will gladly take minutes he'll get and if he'll prove he deserves to play more then yes, we could have (good) problems. Until that happens I won't worry too much. Iniesta is probably aware he can't play every game anymore and future will always be in his hands. I could see him leaving when he'll think he's not useful anymore for the team.
Mina probably also has ambitions to become a starter but before thinking about that he needs to establish himself as a clear #3 CB and it's quite possible he'll get a younger, possibly better and hopefully less injury prone rival for that spot than Vermaelen.
I see other players as backups who by now knows what their role within the team is. Sure, some of them could possibly become unhappy and leave but they shouldn't be too hard to replace if that happens. But it's more likely we'll try to get rid of them before they'll start to complain about their status.