A big part of the identity, and the appeal, of Magic is the fact that every block features a different plane (or at least one that hasn't been seen in a while), and thus a diverse group of characters, cultures, and storytelling can be maintained. Now, each plane tends to have a bit of a "gimmick" - in that society or spellcasting works differently there than elsewhere. The "physical action/athletics/dexterity is part of doing magic" trope is relatively famous in fantasy due to its use in Hong Kong wuxia films and countless pieces of media inspired by them, including Avatar: The Last Airbender and Fullmetal Alchemist. One Tumblr user wondered to storyline writer Doug Beyer why we haven't seen much magic martial arts.
When deetsposts asked, "Can we get more martial artists in magic?" Doug said:
Martial artists aren’t typically part of every fantasy world, so it would depend on having a setting where they would fit. Is that something people would want to see?
(Is this where we get into a big thing about Kamigawa or what? No, I mean, I don't think "martial arts" requires Kamigawa in particular. More planes than that could feature cool disciplined physical fighters. It's just a matter of putting them where they would mesh well with the world. We like meshing well with worlds, you see.)
In the comments, laventuthaslocurri said, "Sounds cool to see as a theme in a set or two," while dapuppers said "most definitely! why must weapons make the hero? besides, not every named or unnamed weapon in the story is made into a card, so that’s not a good reason to exclude martial artists either #bonuscounterarguments"