I think the main issue with Earth and Air is that they don't have a lot of synergy at first glance - granted, we have Dust Moth in Cygnia now, but that isn't necessarily part of the original interpretation of Earth/Air.
The best I can find at the moment is interaction with permanents, be it through control (Earthquake, Pulverizer, SoFree, Shockwave) or enhancement (Animate Weapon, Protect Artifact). What else is there?