The one quality I lack that is eating at me right now is soundstage depth. I have none to speak of. Do any of you?
This is why you cant have it all in the Dojo. You like farfield envelopment, but you are giving other possibilities away doing this.
It's a preference thing like always.
To get passive front back separation needs a symmetrical room setup. Then you need diffusion on the front wall and first reflections.
You can get the soundstage to form a U shape away from you by moving your towers out away from the wall. The drawback of this is usually a thin and off mic sound in the phantom image and louder sounds in the hard panned right\left positions. It comes down to preference. It is neat to have the singer drop back onto a virtual stage.
To really do it right and have separation front to back instead of a U shaped field is with diffusion. Is this real or accurate? No. It is signal processing just like anything else -just in the acoustic domain instead of a DSP. Does it sound natural and pleasing? Yes, extremely so.
Another way of doing it is to have an active setup like LFRs that intentionally send broadband energy in different directions (and time.) When they sum back in your meat computer the effect is three dimensional shapes instead of a flat soundfield.
Putting diffusion on the front wall between the speakers and at first reflection points will give you what you are after without going to LFRs. Going to LFRs is really the ultimate way of doing this because you can have much lower frequencies forming distinct placement in the soundfield. Diffusion can only do so much that way.
Hope this helps!