[JimMorrison]

But the late game revolves around commander units. Commanders with distinctly powerful abilities, and far greater survivability to line troops. The current problem in MP now, is you either summon Tarts, you are into Blood, or you are Wishing Seraphs/Chayots/??. Yes you also have the royalty available, but when there are 20 players, and 12 royalty, you can see they won't make it far around the table.

The point is to provide options for everyone once their line armies start to become somewhat obsolete.

Honestly, I don't see where Air is any more powerful than any other path, in general. In the late game, most paths have ready ways to completely lay waste to entire armies - but few paths have something to supplement your strategy with, once your armies are vulnerable to wholesale slaughter.