If it was 21 personnel, I call it 21 personnel. If it was 22, I call it 22. If it was 12, I call it 12. So on and so forth.
What you say there about sounding like a running play is the point and it's why personnel groupings matter, even if you have guys moving around the formation in non-traditional ways.
If an offense is coming out in lots of 21, 22, 12, and 13, they're pushing the defense into more nickel and base. If you can do that and then split a RB or FB/HB out wide and have him make plays in the passing game, you're creating matchup advantages for yourself.
So going "5 wide" with Adams, Lazard, Deguara, Tonyan, and Jones is a lot different than running out five wide receivers, which would likely prompt the defense to play dime, or even dollar.
And if you come out in 21, 12, 22, 13, etc. and they anticipate you splitting guys out and play dime anyways, you're still in a personnel grouping that lends itself to running the ball. So you can still take advantage.
But people just need to keep straight in their minds the difference between formation and personnel grouping. 21 personnel just tells you who is out there, not where they are. 21 =/= i formation, necessarily. And these designations are anything but obsolete.
One of the pillars of this offense is finding players that can allow you to pass efficiently out of "running play" personnel groupings. Those players make it impossible for defenses to properly matchup unless they too have lots of versatile pieces. You make it so that they can't be right.