I like Grealish and would have him here, but I think we're run into some of the same problems we did with Pogba. Villa play 4-3-2-1 and he's a playmaking AM, operating through the middle or the left (AMC/AML). He is not an #8. He plays with McGinn and Nakamba behind him.
The problem with an AMC or LW/AML is that those two positions are occupied by our 2 most consistently productive players, Bruno and Rashford. Do we not need more depth you might say, especially if Pogba leaves? How do City fit so many AMs in their squad?
Well, yes. I'll reiterate that I would have him here, finances permitting, because he's a good player. But depth is not our top priority, we need an #8 that is better than McTominay and VdB to play next to our DM. We need a #6 to replace Matic and to compete with Fred. We need a reliable CB partner for Maguire because we still concede too much from set pieces and 3 out of our 5 CBs are always injured. If these positions can be sorted I'm all for adding Grealish.
Same applies for Kane. We have Cavani and Greenwod upfront. Kane is better than those, but is it where we need improvement the most as a team. Arguably no.