Grealish for me is yet another example of a decent enough player, but at a level or two below the player(s) he has replaced.
We have a few too many of these players in the side and when coupled with our mainstay best players being older and in some cases suffering a drop in performance levels, it stands to reason that the overall quality of the side dips on what we have seen previously.
There is nothing wrong with Grealish, with Akanji, with Ake etc etc. They are all decent enough players of a certain level. Unfortunately for them and us, their level is significantly below what has gone before. They all play far too often in a side that is trying to win everything.