It depends what you mean by mentally weak. I certainly think there's an element in our dressing room who are unable to cope with the pressure that being at a club like City challenging for honours that we are, and I don't mean often pointed examples like Nasri but more more protected players like Kompany and Silva. I also think this extends to large sections of the fanbase and it creates a feedback loop that makes the team nervous which makes the fans nervous which makes the team more nervous, etc.
The big thing I have taken away from those title runs seems to be different from other people. They see us coming back from 10 points back as a heroic achievement of pulling through when we're really under pressure. This isn't the reality as I perceive it, I see us unable to keep toe to toe with teams across a season and only when we're so far back that we're no longer expected to win it and all expectations have gone are we really able to perform to our highest standards. A standard that the teams under a Mourinho or Fergusion would have done without needing that pressure lifted in the last stages.
Our best run in both title seasons have always been once the title was pretty much gone and required spectacular collapses from others. You can see it in the Champions League too, where we are crippled by nerves and pressure and desire to do well to the point where the first signs of difficulty almost become an excuse for "here it goes again".
I have always put this at the door of Vincent Kompany who is the embodiment to me of the mental problems I see in the team. He's the definition of a person who believes that trying harder will make a situation better instead of the more mature approach that just calming down will make a situation better. I've had this conversation on here numerous times in previous seasons but will yet again point to his pre-season work - he thought the way to overcome his injury problems was again to do the only thing he knows how to do and try harder, get into the gym early, make himself stronger. Now he's injured again a few weeks into the new season. He has always had a rather immature view that comes through in every part of his game, you can see it when we go down and he's attempting to inspire the team not just by doing his job but by doing everybody else's too which whether anybody likes it or not means that he cannot be doing his job to the required standard. He attempts to charge around and cover for everyone which hangs him personally out to dry, and as a centre back he should be absolutely solid with his partner and let the full backs and defensive midfielders do their own job.
Kompany is the most English of centre backs despite being Belgian. Never seemingly understanding the value of calming down rather than ramping up.
You can argue many different causes over this, but I cannot think of a really high pressure game where Silva has displayed his incredible talent. Might be a slip of memory but he certainly isn't somebody who I think will be pulling us through in those games unlike an Aguero or a Yaya.
Yaya is a good example of the attitude that I'm talking about. Despite people screaming at him for waltzing around the pitch unlike Kompany who charges everywhere, he is rightfully recognised as one of the best midfielders in the world. He is arguably City's biggest "big game player", scoring in Finals, Semis, great performances in Europe here and there. Definitely can be criticised for his lack of consistency but he isn't a player who gets overawed by occasions. Aguero goes without saying.
I think it's sensible to now wonder if there's something inherently wrong with the spine of our team in regards to their ability to cope with the really tight occasions, often against the 11 man defence, or really high profile occasions where we need to go to Stamford Bridge and win, late in the season.
Winning all of our titles from 6-10 back has created a false narrative around us. We see ourselves as people who came back from the dead whereas more focus should be put on asking questions of how we managed to die in the first place, only performing after the pressure has subsided allowing us to take the trophy.