@AP88 disagree with probably all points so I'll try to break it up.
United became a force in Europe in the mid to late 00's when Fergie brought a lot more foreigners to the team compared to a decade ago. For example the team that won CL in 99 was almost exclusively made of British players. The only four players that were first teamers at the time were Johnson, Stam, Schmikes and Yorke. Of course Ole and Blomqvist played some part for example but the best team we could field consisted of British/Irish players like Irwin, Gaza, Beckham, Giggs, Keane, Scholes, Butt, Cole, Teddy, May etc.
The best Arsenal team that also made it to the CL final had 2 English/British players that were regular part of the Invincibles - Cole and Campbell. All other key players and even rotational players were foreigners. The Chelsea team that came to prominence was foreigner based and managed by a foreigner who implemented his ideas - Mourinho. The best Liverpool teams that achieved some success internationally had foreign managers in Houllier and Benitez and again imported a lot of French/Spanish players. The City team that won the league after decades won it under a foreigner and with key players like Aguero, Kompany, Balloteli, Dzeko, Silva - all foreign import.
Even Leicester won it under Italian manager and absolutely crucial players like Kante and Mahrez.
The most English team lately is Spurs and you can see how well they are doing in Europe.
All the best club teams we've seen in England(bar Fergie) are result of foreign ideas who brought in players to suit their tactics and style. If you're looking at identity and local players/mindset - well look no further than Big Sam, Moyes, McLeish, 'Arry, Pardew, Lambert, etc - that's the cream of the crop.
You take out Ronaldo, Modric, Kroos and Marcelo this season out of that Real team and Zizou would've been sacked at around February. He has brought some Spanish players, but the core is composed mostly of foreigners. I wouldn't say he did anything special to be honest.
I recall the last 2-3 years of Gaza's career at United, many of the fans were shivering when they saw his name on the team sheet and many were asking when he will retire. Of course loving the shirt and being brought up from the academy is great and I'm all for that, but we can't expect every winger from the academy would turn to be the next Giggs or Beckham. If a foreigner is better than him and the club profits more with a foreigner on the team sheet I don't see the issue.
I don't see the relevance here as City are doing better than us lately in the championship and they've won 2 titles in the last 7 years, the points margin is irrelevant.
Again really irrelevant. If you are good enough - you are good enough. The minute you become disruptive another one comes to take your place. Having a wider squad also helps so you don't have your first team place guaranteed.