It is easier (and that's still a tough assignment) to get two drivers to work together, rather than three or more. Cabinet resonances/CROSSOVERS are a very big deal. True the bass extension is compromised a tad, but isn't it on most speakers? There is no panacea here, of course, but monitors can become addicting. True, the footprint, in the end can be just about the same given the stand and all. It's probably a wash in that sense. A world class monitor's, (other than bass) midrange and highs can stay with the biggest boys, still in a relatively smaller space, given the use of a sub. A monitor on a quality stand, (visually we're talking, now) has a airier look. More space under the speaker (perceived, because of openess) has, to me, a nicer eye appeal. Everthing is a trade off in this audiophoolish world. I think you can attain greatness with a killer monitor, sub, and stand, less expensively and easier (if you will), than you can with a floor stander.
peace, warren