Is DEQX a game changer?

Ozzy, I think your logic is sensible and will apply to many.
It costs (next to) nothing to 'tinker' with ideas for room treatments and most will accept the musical happiness they can obtain thereby (and I have experienced huge improvements that way); and of course we're all well aware of the potential for significant change due to the staggeringly quick evolution of digital and communication (transmission) technology. But, this conversation confirms the units do seem to offer previously unavailable, perhaps unimaginable, options to a serious music lover who wants more 'you are here' feeling. We live in exciting times don't we.

It seems to me that the user friendliness of the DIRAC was a major reason Stereophile seemed to prefer it to the DEQX. As far as I can tell, the DIRAC might not offer the advantages of custom x-overs that the DEQX offers. For those not interested in by passing their existing x-overs, or the expense of additional amplification, there could be substantial cost savings.

Where did you see that "Stereophile seemed to prefer it {Dirac} to the DEQX?'

^"The best 67 audio components of 2014"

I think you may be misinterpreting a paraphrase of my published statements. If I may, I would edit your interpretation to say: "It seems to me that the user friendliness AND COST of the DIRAC was a major reason Stereophile seemed to RECOMMEND IT OVER the DEQX."

Dirac is cheaper and easier to use but not as capable as DEQX. If DEQX made a multichannel version, I'd use it.