Grealish is apparently the most fouled player in the league since they started collecting statistics. He draws the majority of those fouls because he has an incredible ability to take the ball extremely close to the defender; he can then shift his weight either way to unbalance his opponent, so in that sense, he’s extremely similar to Mahrez, only playing on the left. However, when Grealish shifts the defender he tends to create more space between himself and his opponent than Mahrez, and that allows him either to cross unopposed or drive into the space he has created. It is at that point when he often draws the foul, either because the defender takes him down or Grealish is quick enough to determine that he’ll gain more of an advantage from the free kick than he would from staying on his feet: footballing intelligence. Another attribute he has is that he has incredibly powerful legs and a fairly short running gait. So, in that regard, he’s probably more like Aguero in that he can use his centre of gravity and drive to burst through defences.
Of course, these are only footballing positives and have to be placed on the scales against the weight of his seemingly endless social negatives: hair band, hairstyle, punchable face, histrionics, driving offences, and sexual peccadilloes.