I think we all need to be aware of the past. We all were drowning in "wet" bass. What is the balance of the wet vs. dry is individual. So one might rightfully so call ART too dry even with +12dB curve. Content we listen to was mastered without ART, so what ART does in not really what was intended anyway. But IMO any other traditional solution is not really doing us a favour.
As far as the Mad Audio video, the guy is pretty cryptic. I have actually no idea of what he did in settings or how it measured up. Nor what he is using or what are the limits of his equipment. I guess he would want me to do additional work, which will obviously not happen. He seemed to promote the small B subs though, so there is a conflict of interest right there. All Youtubers and bigger sites have to live off something. We are on a forum where this seems to not matter, which is great.
As to the fundamentals of Mad Audio claims - I can't follow that. He apparently claims that directional bass seemed to get so much better with his implementation? Also strange (or perhaps intentionally appropriate) that he chose the Frankenstein movie to test his experiment of combining parts that are traditionally separated.
That goes against my own experience where I have 4 equal subs and large (50-150hz) supporting speakers and based on the filters, ART always chooses the support of the subs in the low end range. This will still result in directivity of the bass if encoded in specific channels (not LFE), but will not provide the same air pressure clue as it would in the full range system without any bass management for the mains (would need to be reference or so level). ART is not designed to do that, so I wonder what is that guy hearing. Appreciate that every room and every system is different. He seems to have pretty good gear and the room, but not sufficient disclosure for advanced members.