Hansi Flick must see Gavi as a good player to have in Barcelona's main line-up next season. Romeo, Ilkay Gundogan and Roberto certainly have more experience than Gavi, but in terms of energy I think Gavi is still quite good compared to them. Gavi can sometimes be decisive, it has developed well under Xavi for several seasons.
I agree with you. Gavi is one of the best young players in the world. He was a wonderkid from Spain several years ago. It was very unfortunate when Gavi suffered a long injury which made him miss several important matches. With Gavi's return, I am sure Barcelona will find their best performance again. I can say Gavi will be one of Barcelona's important players next season. I see Gavi has a playing style that is almost the same as Xavi. I'm sure Hansi Flick will include Gavi in the starting XI next season.
Gavi is a gem. But holding this player in the team won't be easy at all. We know a player with talents like Gavi and his age is a player any team wants to have him in the team and this can make any team to spend good offers for hiring Gavi from Barcelona and since Barcelona doesn't have enough money, it's not surprising to see them losing this player soon.
However, I think now since he is getting back to the good form, this can be a piece of good news for Flick since he can again help Barcelona at the start of the season and he won't miss the summer pieces of training hopefully.