Air Gear's biggest problem is that Oh Great tries to hard to introduce and explain so many things at once that it's hard to keep up with what's going on. Tuners? Kings? Regalias? Sure, those could be kickass if explained right, but I wish he'd go back to how it was in the beginning.
The characters are pretty cool too, interesting and entertaining. My only main gripe right now is how he's focusing so much on Agito instead of Ikki, who's supposed to be the main character. Agito is becoming the Sasuke of Air Gear.
Still waiting for Kazu's chance to truly shine to come up. He said he learned how to use the flame regalia, but they haven't gotten around to showing it yet.
Buccha needs a little more attention. Hopefully the foreshadowing of a bigger role him won't be ignored.
And Origiri's just there for the lulz.