I guess I'll start
I chose Air. This isn't because Air sucks; this is because every other element has a theme or a focus which makes it excel in its area, and I'm just not seeing that with Air.
Control at its finest.
Capitalizes on dying creatures.
Sheer, fast damage + perm control.
Epic offensive capabilities + perm control.
Very nice creature control.
Card control.
Extreme when lucky + perm control.
Great offense + great healing
Lockdown creature control.
Healing and overall defense
EVERYTHING!!!! (Defense and immortal offense)
Umm.. ... umm.... Flying Weapon?
Basically, it lacks an "identity" like the other elements do. It needs this, and it needs power to boot.