In hindsight, if Gündogan's leaving shows anything, then that Flick isn't as spineless as some fans assess him to be. Gündogan was a Xavi transfer, he wanted him above anything else and under Xavi he played every game. Now Flick comes around the corner and when rumours about Olmo started to appear, many fans including myself critized Deco and Flick for taking away Fermin's playing time for someone, who is not needed.
But the situation is now that Gündogan is leaving and Deco is working to extend Fermin's contract. Turned out it wasn't about Fermin, but Flick wasn't that enthusiastic to keep Gündogan.
And if you think about it, it only logical. Flick demands a strong physical performance, to press non stop. You can't do that with a 36 year old Lewandowski and a 34 year old Gündogan behind him. Our pressing would have had more holes than a swiss cheese. Gündogan is still a class player, but in combination with Lewandowski it wouldn't have worked out for Flick.
Flick confirmed there was a talk between them and I think in this talk Flick told him he isn't an undisputed starter anymore like he was under Xavi. Especially, because in Flick's system there is only one OM spot and not two. Olmo, Pedri, Gavi, Fermin. All young players more capable to perform better in Flick's pressing as well as their salary is way lower than that of Gündo.
And I think Gündogan is too proud to sit on the bench for some kids as former captain of City, so he asked to leave as a consequence and the club has nothing against it, as it helps with their salary limit.
If it happened like that and it sounds very logical to me now, it's the best for all sides. A professional assessment of the general situation without unnecessary feelings. Xavi wanted to get rid of Lewy, Flick didn't count on Gündogan. Every coach has his preferences and Deco listened to Flick in this matter.