I'm not that much of a fan. He has all the skill in the world, but gives the ball away far too often, and gets bullied too easily. That said, we don't have anybody else in that role other than Grealish, and the least said about him at the moment, the better.
I'd be tempted to play Sinclair in his spot instead.
Very flaky player. Not what's needed in a struggling team, he'd look good in a good team surrounded by like minded players. We need to get ugly, kick a few people and get the ball in the box at any opportunity, he doesn't fit into that.