Speakers for room size that provide greater detail.

Here I respectfully disagree with your post. The old adage "Garbage in = Garbage out" is still apropos here. A high end speaker will not sing properly if not fed the right input. The Rotel puts out a lot of power at 200WPC, but it is all AB, no A/AB. I cannot find it’s stats into 4 ohms, so I’m guessing that it doesn’t nearly double, which would explain why people describe it as dry & sterile.

All Class AB amplifiers have some bias into Class A. For some, that bias is minuscule, but since the Rotel outputs 200 WpC into 8-ohms, chances are the designer(s) biased it for class A for ≈ 1 watt. 

Crossover distortion is not as audible as some manufacturers would like us to believe anyway. 

Not being able to find a spec for 4-ohm loads is meaningless, because many manufacturers’ amps fall short of their 4-ohm ratings anyway. Or they understate the 8-ohm spec merely so they can accurately claim the 4-ohm spec. 
 

You are dealing with some very basic physics and acoustics here. Regardless of brand, a 6" stand mount will be limited to about 105dB @ 1M maximum output with a 100W/ch Amp (there's only so much air a 5 or 6" woofer can push below 100Hz. That will decrease 6dB for every doubling of distance, so at 15 ft, those speakers can only deliver about 92dB, for the pair, add 3 dB, so the peak SPL at the listener will be 95dB. That's just not enough speaker in a room the size of yours.

Moving up the scale, a 2X8" Floor mount will top out at around 112 dB each, so 7dB higher than a stand mount, and 102dB for the pair at 15 ft. If the speakers can handle the power, a 200Wch amp will give you another 3dB, so peaks of about 105dB. That's about the lower limit for realistic reproduction.  Ideally, you want about 10 dB more capability. 

A JBL 4367 has a sensitivity of 94 dB 1W/1M and a rated power handling of 300W (peak). That should translate to (following the same math) 107dB, but because the 90X40 horn focuses the energy in a smaller area, the 4367 will actually play louder - as much as 6dB in room. Now, we are talking about a speaker that will fill a large room with realistic sound levels, while minimizing the effects of the room (because the horn is bouncing sound off the walls, floors and ceiling far less than a direct radiator). That improves what acousticians call the 'critical distance', the point at which the direct sound level is equal to the reverberant sound level. And that is a key to sound quality in larger rooms, because the delayed reverberant sounds are delayed enough to be very audible and impact sound quality dramatically. 

This is also why acoustical treatments are critical in larger spaces, as they serve to both control reflections and reduce the reverb time (RT60) in the room to acceptable levels for serious listening.

OK, that's a lot to digest, so here's the 30 sec version. 1) Speakers designed for 1600-2000 ft3 rooms simply can't cut it in a 4400 ft3 room. Horses for courses. 2) Acoustical treatments, nice in all listening rooms are near mandatory in larger rooms. 

Nucleardog61 - how are you progressing with this? I am very curious as to what you find because I have similar situation. Pleas update us when you get a chance.