I think Valverde deserves a lot of credit for establishing the regular list of players. Much better to settle on the right-sized group than do what Lucho did.
1 keeper
1 LB
3 CBs
2 RBs, alternating
Pretty much 1 DM, Rak as the only alternate
4.5 midfielders (S. Roberto is the .5). Iniesta and Rak first choices, lots of subs and rotations.
2 + 2/2 forwards. Vidal is a forward, now.
Abandoned: Verm, Digne, Gomes, Arda, Deulo, Cillessen, Paco. Rafinha will be ignored when (if?) he gets healthy. It's better for the team to let all these excess players rust, so that a right-sized group can all keep sharp.
Valverde deserves a lot of credit getting improved play from Messi, Iniesta, Rak, Alba, Messi, D. Suarez, Vidal, S. Roberto. Forcing L. Suarez to play out of position has hurt Suarez a lot, but helped the team more by getting more from Messi. Integrating Paulinho and Semedo has gone very well, likely to improve as the season progresses.