He played really well in the RCM role, when Cancelo was tucking in on his side.
This gave him the role of basically being everywhere he needed to be, and with his engine and control, I think that suited him perfectly. Throw in the odd goal and assist in that and we have a very good player.
I think you neuter that when you play him up top in a double false 9, because if we press, oh those 2 strikers are bypassed, okay then he is now useless, his running, while alot, is pointless up top.
The problem was that Cancelo started making mistakes and got dropped (as did Rodri), so without Cancelo we saw an inferior version of Bernie.
I really don't think it's a coincidence that we saw the best of Gundogan, Bernie and Cancelo, when all 3 played together. Gundogan benefitted from Bernie dropping deeper as well. While he plays the midfield 2 role fine, I like Bernie doing that, and letting Gundogan higher up.
Really hope when Pep analyzes the season again, he sees that period when we were at our "peak", those 3 were absolutely massive to that. Hope he isn't sold.
Edit: Just to add, since Pep played that last game without Dinho and Rodri, I believe the first time all season, I don't see why we can't play something like this:
Foden------------Striker---------Mahrez
------Gundogan----Bernie-----KdB
Just play Gundogan, Bernie and KdB in the midfield, then when Cancelo tucks in, those 3 have freedom to push up.