We've got so many players who are absolutely shite with the ball and it just looks so comical when you play them all against City.
Smalling, Young, Matic, Herrera, Lingard, and then Lukaku when he came on... all of them absolute garbage with the ball at their feet under the sort of pressure City showed. They were humiliated again and again. Obviously we already know that Smalling, Matic and Lukaku are hopeless with the ball in any situation really, even under no pressure. Fellaini is pretty shite with the ball but these other guys make him look like Pele.
Building any sort of coherent attacking team is not going to be possible with a spine of players that are so fundamentally bad at basic ball control, weighting their passes, or even just simple awareness of what's going on around them.