This is just not how it works. We are evidently not being coached to adopt a pressing game - and certainly not a pressing game of the extreme intensity of Dortmund's. You can't just add a player whose last team played a certain style and expect us to suddenly adopt that style. The only person who can change our style of play like that is Fergie. And either because he doesn't want to, or because he's fairly hands-off in training and Mike 'the beanbag' Phelan takes the lead, it doesn't look like happening any time soon.
1 player in the engine room can make one hell of a difference. If your pool consists of two players nearing 40, a couple of young players who struggle to play at the same tempo for 90 minutes, a fella with a 'chronic' condition and Michael Carrick, you have to set your team up to get the best from them.
If we spent big in central midfield and for arguments sake signed Gundogan and or one of the Benders (I'm fully aware that none of the above are likely to happen), we'd certainly look at ways to include their current playing style into our system.
Throw in the way Kagawa played at Madrid, a player who is quite clearly growing into this side, Welbeck's insane work ethic, Rooney, Valencia and Carrick who has played in every possible way you can think, it's possible.
In a different example, consider how incredible the change was in midfield and thus the whole team when we signed Carrick. Granted, his impact was more on the passing side of things but that little piece in the jigsaw had a huge impact on the success of the last 7 seasons.
A player like Gundogan could certainly lead to a shift in the system providing we incorporate his strengths and strike a balance with Carrick's strengths. It won't be entirely symmetrical to the way Dortmund play because in reality who's to say that we can't develop a superior system whilst incorporating factors from the way we currently play and their high-energy pressing game?