There are several points I don't understand:
1. "Bigger floor-mounted boxes may have coloration from cabinet vibrations and resonance which can impact the coherence and detail of the midband."
It seems to me that any poorly designed cabinet can have issues, small or large. For a comparison to matter I think we'd have to compare well designed towers vs well designed bookshelfs.
2. The point keeps getting made that stand mounted speakers and subs are easier to position in a room to optimize room acoustics. Why would this be any different from floorstanders. The Aerial Acoustics 5Ts on heavy stands were no easier to move or position than the 6T towers. And subs aren't exclusive to stand mount systems so they can be used with towers too.
I'm just playing devil's advocate here. I'm not in the market for speakers and this was just something that puzzled me.