Let me put it this way, Scott Adkins could do the John Wick films (they’re even tapping him for part 4) but I don’t think Keanu could do half of the aerial acrobatic kicks that Adkins is asked to do in virtually any of his films, especially without the benefit of wire work that he was afforded in the Matrix films.
I'll hop in once more as I think I now understand better the differences in our opinions. The above quote is there only because of its reference to the acrobatics (and to tag you, of course).
To me, aerial acrobatics are mostly gymnastics, not martial arts. Some arts have them in practice, but they're mostly just meant to develop certain kinds of athleticism. That sort of stuff may look great in movies, but more often it's just stupid (IMO) like Adkins trying to finish a downed opponent with a knife by lunging into the air, doing horizontal triple lutz, and landing flat on his back beside his foe.
The ability to do such acrobatics doesn't define a "true" martial artist. It doesn't say anything about one's ability to fight, either. If it would, the Olympic gymnasts would be the greatest martial artist of all time. That way of fighting is just one style of cinematic fighting and apparently, it's a style you prefer.
I have no doubt that Scott Adkins can do many things Steven Seagal never could. Based on their credentials, I'd still rather call Seagal a master martial artist than Adkins. Despite possibly being an ass and a pathological liar, Seagal still has real and high credentials in Aikido (as far as I know, much more than Adkins has in any martial art). More importantly, though, I much prefer his style of cinematic fighting and the fact that in his films every crook he meets isn't a martial arts expert.
But yeah, I do like Adkins but at the same time, I wish he'd be in better (and better choreographed) movies.