hey what do you mean by heft ? I have kef speakers.Staging is probably less of an issue. Compact speakers actually do well for this sort of thing.
Its the scale of sound you will miss from small speakers like the B&W. I have a pair of Budget B&W floor stand speakers and a pair of KEF Eggs as surround. The KEF's barely have any heft to their sound. I can't see a world of ever using them as mains and getting by. They don't work. You will likely end up in a upgrade bug situation rather quickly.
While two front main floor stand speakers will take some floor space, they will fill the area with more sound, even at low volume levels.
I have only noticed, they are not fast enough or not separating enough in trance music.