I've always been a Nani fan and would like him to regain his form and nail down a first team place once and for all. He is one of our relatively few genuine goal threats - think about that for a second, when we see the likes of Valencia, Young, Kagawa, Januzaj (he is quality but not a goal threat yet IMO) and - aside from the past few weeks - Welbeck.
When we lined up against City and got smashed this season, out of our front four the only player you could really see creating anything was Rooney. So City just marked him out of the game and the other three were useless.
I agree with the notion that Nani needs a run of games and is generally useless as a squad player. There are some players who can come on 60 minutes into a game having not played for weeks, and immediately look like they have never been away - Nani is not one of those. He is like Rooney in that he needs a consistent run of games in order to perform, if we cannot or will not offer him that, then there is no point keeping him.