One thing I’d say about a Stage is that you should put a really good absorber *behind* the speaker. Any
wall reflections are magnified with an open panel center because it is not angled out like a L/R might be, and the rear wave will bounce off the wall behind the speaker and come right back through it, delayed, causing some nasty comb filtering. This destroys the mid-range and high ‘balance’ and of course is not as good as the L/R sound.
Note that I said open panel, models like the Motif might not be as susceptible (although they have it to a degree) due to their woofer box being behind the panel, and the factory design treats the box. The Logos had not treatment and comb-filtering was a serious problem on that model.
Now, as for listening to 2ch audio on a 3.1 or 5.1 setup, I have a strong preference for the later using the Meridian TriField process. But then again, I designed and built a center just to be able to have seamless multichannel audio.
So part of the problem is that since very few center channels actually can keep up with their L/R pairs, it is probably better to listen in 2ch or 2.1 modes. But not because it’s intrinsically better, only because unequal speakers will rarely blend well.