Ok, now that we have seemingly locked the Griezmann transfer, this is what I would do with our squad (I know, possibilities of this happening are extremly slim, but anyway...)
In 4-3-3 formation (although a lot of these players are usable in a lot of different positions in different formations)
Goalkeepers:
Marc Andre Ter Stegen
Jasper Cillessen
Left Backs:
Jordi Alba
Lucas Digne
Centre Backs:
Samuel Umtiti
*Jonatan Tah / Matthijs De Ligt
Gerard Pique
Yerry Mina
Right Backs:
Sergi Roberto
Nelson Semedo
Central Defensive Midfielders:
Sergio Busquets
***Oriol Busquets
Centre Midfielders:
Phillipe Coutinho
Andres Iniesta
**Thomas Lemar
Ivan Rakitić
Paulinho
***Carles Alena
Forwards:
Lionel Messi
Luis Suarez
Ousmane Dembele
Antoine Griezmann
***Jose Arnaiz
* I think that we need to sit down with Verminator after this season and discuss if he wants to move on to get regular play time. I think currently he is very happy with his playing time right now, but that can change when Big Sam returns. He is also 32 and injury prone. If he decides to go in the summer, I think we should either move for De Light or Jonathan Tah (who has his release clause at 20 million Euros, apparently).
**There has been talk quite a while ago that Monaco wants Andre Gomes. If I was Barto, I would try a cheeky offer of Gomes + Denis + 30 million for Thomas Lemar. Why you might ask? We just bought Coutinho... Well, considering that Iniesta will probably retire in 2-3 years time and even now he doesn't play more than 70 minutes per game (usually a lot less), I'm afraid that we will become very dependant on Phil in terms of creativity.
So if Phil gets an injury when Don retires, we are fucked again. If Phil is injured and Iniesta needs to be rested, we are fucked again. To prevent that, I would buy another Iniesta type midfielder. I see Alena more as a heir to Paulinho / Rakitić. Needless to say that both Lemar and Coutinho can play on the wings too, so they would both get enough of playing time.
***Promoted from the B team.
With this squad of 23 players (smaller squad, which Valverde apparently likes), we could do Lucho-like rotations, without losing a lot of quality in each position and we would finally lose the deadweight players. We would have 3 technical midfielders and 2 box to box midfielders and Alena, who is a mix of those two traits. Also, Roberto can fill the gaps in the midfield if needed.
Out: Gomes, Denis, Vidal, Rafinha, Deulofeu, (Vermaelen), Paco
But this is just a brainstorm of mine...