I see this is the cantankerous way you've decided to go about this morning, you're comparing apples and oranges, Ronaldo (and pretty much everyone who ever returned to their old club) came back to different managers, playing styles, players, hell even directors/chairmen, Gundogan is literally coming back to the club exactly how he left it he'll slot in immediately and it certainly improves us going into the season.
As for one of your further posts about us not struggling against united, we were shite (understandably) that day, could and should have lost the game.