United will be fine, they already saw off Spurs, beat Villa in there own backyard, and crushed invading infidels from Brugge.
Depay looks to be finding his feet fast, which is usually a few months in the English game.
Yes, you could have got Otamendi and Pedro for the price of Raheem Sterling, but the team looks fine albeit slow paced (passing wise). Liverpool, Spurs and Arsenal havent improved that much yet.
It just the pending transfers from MCFC and Chelsea that will make the United suitation look worse, when really they have bought well and have a decent balanced side, maybe not a fully balanced squad but that will come soon enough.