Well...Arsenal - they have two good attackers in Ozil and Sanchez. That third spot is usually someone like Wallcott, Ox, Ramsey (who isn't winger), Wellbeck or some other crab. Cuadrado is better than all those mentioned. Why do you think Arsenal fans are so desperate to sign Mahrez? They're severely lacking on one side.
Tottenham - again, Alli and Eriksen are great but Lamela has been inconsistent on that right side. I would prefer Cuadrado to Lamela, who has been underwhelming since joining.
United - they have no genuine wingers. It looks like they're going to push Henrikh out wide (he is best used as a 10), have Rooney in the middle and shift Martial to the left side to accommodate for Zlatan. A front three of Cuadrado, Henrikh and Martial would be better than Henrikh played out of position, Rooney (cooked) as a ten and Martial on the left.
City - they're overloaded with attackers, and like Cuadrado, Nolito and Sane are unproven in the PL. Outside of them they have KDB, Silva, Navas and Sterling. Sterling is a f***ing donkey and Navas is on par with someone like Pedro. At the moment I would have Cuadrado, KDB and Silva.
You also say Serie A is slow, which I agree it is, but Cuadrado was also good at CL and the WC, so he's proven in other tournaments against high quality opposition. At Chelsea, he was brought on for small periods when we were defending one nil leads so who knows what Mourinho told him to do when he went on. A lot of the time it looked like he was trying to hold the ball up, which isn't his natural game.
He'll get a better opportunity under Conte, who will also know how to use him properly and I think you'll be surprised.