I don't find the Qsuite too narrow, but I do find it's much better to be in one of the suites where the seat is away from the door (eg directly at the window) rather than snug up against the door and partition, as the latter makes me feel a bit cramped, and if working away on the laptop, one's elbows can often hit the wall.

Agree that Vantage XL and Super Diamond are very good on their own but no massive leap from Cirrus. Cirrus has sort of hit the 'sweet spot' for Cathay, so no sense changing unless it's to something which can be considered as markedly better.