It's very obvious that Emirates will need to increase their capacity to MAN. As people have said, they've reduced cargo capacity by a large amount (something which has kept SQ at MAN for god knows how long so obviously is very profitable!) so therefore either they need to increase cargo operations via SkyCargo or introduce a morning service.
I believe the latter will be the most effective. It simply needs more Y seats and cargo so therefore the 773/77W is the only option...
Regarding DUB, it is very unfair to compare MAN and DUB to the USA. DUB is pretty much 'mini-USA.'
Manchester is perhaps poised to benefit more from the 3rd runway cancellation,because it has managed to maintain its links.
I don't think even we realise how beneficial that is going to be to MAN...