He took the squad to be performing levels above what they were. He also had a lot key signings during his time that were brought in, not just one or two. Wanyama, Trippier, Deli Ali, Sissoko, Lloris, Dier, Alderweirald for example.
I find it lazy to suggest he inherited a very good team. Ultimately he had them punching above their weight for the vast majority of the time he was there. He did the same at Southampton too, taking them to their best league finish I think in Premier League history. If I'm not mistaken he also overperformed at Espanyol.
I also don't enjoy lazy posts that point to his ceiling as a manager. He's 49. Managers grow, adapt and learn from experiences just like Players would. To insinuate a manager is never good enough or has an low ceiling when they are so early on in their career is just weird to me. Poch is 3 years younger than Ten Hag and has done well in 3 clubs across 2 leagues. Ten Hag is doing so well but he is so far only proven in Holland.
Poch is performing below par at PSG due to a host of issues, some his and some not. But the jury on him is definitely still out.
Anyone calling him a fraud are just overreactive. He'd be a fair choice for our manager even though I'd rather see Ten Hag + Rangnick trusted ahead of him (in that order). Even though he's 3rd on my personal list, that doesn't mean he's a failure or a bad manager or not suited to a top club. He can still be a big hit for anyone, including Manchester United.