Question is not whether Werner was good enough for United/Spurs. People listen way too much to stupid opinion-building pundits like Burley or Nicol.
Let´s put some "peak" stats to it....
Champions League stats:
Werner 43 games / 17 goals (0.39) / 7 assists (0.16)
Rashford 33 games / 12 goals (0.36) / 5 assists (0.15)
Antony 15 games / 3 goals (0.20) / 4 assists (0.26)
Martial 40 games / 6 goals (0.15) / 6 assists (0.15)
Werner (Chelsea) 89 games / 23 goals (0.26) / 21 assists (0.24)
Werner (Chelsea/Leipzig/Stuttgart) 346 games / 125 goals (0.36) / 67 assists (0.19)
Rashford (United) 383 games / 126 goals (0.33) / 73 assists (0.19)
Martial (United) 317 games / 90 goals (0.28) / 55 assists ( (0.17)
Antony (United) 65 games / 8 goals (0.12) / 3 assists (0.04)
Overall Werner´s numbers are eerily similar to Rashford, slightly superior.
As a workhorse, assist man and press initiator Werner would have been a reasonable gamble as a loan + cheap buy option. Question is what is going on with him mentally/physically right now. He has been very poor for Leipzig recently.
As a United fan, I´d be encouraged that the new people in charge base their decisions on stats and value, rather than what ESPN pundits think. You´d think Chelsea fluked their whole CL run, when you hear people talk about Mount, Werner and Havertz. They bring a lot of the intangibles you need to be successful: workrate, unselfish, tactical smarts and discipline, plus sufficient end product in a working system.