Saw quite a bit of him at Chelsea, and then for Fiorentina. Unless he's massively improved at Roma, he is the epitome of the fast winger who looks amazing on Youtube, but is immensely frustrating to watch on a weekly basis. He's the kind of athletic winger the Premier League has seen a lot of - the type who looks incredible one week and absolute shit the next. The "he has all the ingredients, but if only he could figure it out..." type. They never do.
He's not a particularly good dribbler, unless kicking the ball 10 yards past a defender and trying to recover it himself constitutes good dribbling. His technique and decision-making can fluctuate anywhere between adequate to Bramble, often in the same game. He's at his best in an open game with space to run into, something he won't see a lot of at a big club, especially not in the Premier League.
Pretty sure Rodgers - or the nefarious "transfer committee" at Liverpool - were interested in him before Chelsea came along, so he might get a chance there. I could see him being successful in Klopp's system for a couple of months, leading to lots of hot takes about Klopp vs. Mourinho, and general hysteria, before he inevitably returns to his original level and we pretend those discussions never happened.
The only other feasible "big club" option in England could be Arsenal, if Arsene decides he wants to relive the Theo Walcott Experience (™). They're already reliving every season on a loop, why not take the next step and relive the players that led to them reliving every season? Loops within loops within loops. Feels like something Arsene would be into.