I'll admit to knowing very little of Grealish and his footballing ability, but I am unconvinced that he is capable of filling the boots of world cup winning captain Dembele. That's a big ask for an established player of genuine quality, let alone one that has only ever experienced championship standard football at best. He may very well be a huge talent (I bow to Poch's judgement on this front) but is he ready to enter a side that has aspirations of finishing in the top 4 of one of the worlds most competitive leagues? I'm sceptical about this.
You come across as an extremely objective poster. Rare for an oppo on here.
I don't think we'd replace Dembele with Grealish, at least if we were to do that I'd be extremely disappointed. We would need at least another CM if we sold him, potentially somebody like Ndombele or a similar player with the physicality to be able to replicate the role that Dembele has in our team. His ability to resist the press and retain possession is otherwordly and I doubt very much whether Grealish would be signed in his place, it would be incredibly naive to do a like for like swap.
I see Grealish as being signed either alongside another, more defensively inclined CM, or signed whilst we keep Dembele for another season. As you say, it would be placing an immense burden upon his shoulders to come in and replace a fan favourite player who possesses extremely unique qualities and is very important to our system. Injuries are catching up with him but when he's really fit and on his game he can be a difference maker for us, his performances against Juventus, Liverpool, United etc were excellent. We will miss him regardless of who we replace him with. Grealish will be eased in slowly I would think, similar to how Pochettino used Alli. His record with developing young players is excellent so I absolutely trust his judgement on this front on whether Grealish would be ready or not.
Thanks by the way. I generally try to be somewhat objective and not let the ol' tribalism blind me when I discuss football, especially since I'm on an opposition team's forum.