RB one has higher cooldown, but you get 150 range for one point while normal starts at... 90 I think? So for the sole purpose of pushing, one point is fine. And no, it doesn't get range increase.
And about the air combo's, I'm referring to myth raids where 99% of the time I'm working with my party to air combo. RB Kungkungi re-airs grounded mobs so my team's spam can continue to hit them, and RB kungkungi has impressive vertical range, so I can hit stuff that's still in the air. Also keep in mind most stuff that can't be air combo'd in myth raids can't be pushed either, which helped me decide to drop maxing RB shung.
And no... I cannot do sophisticated air combos because my fingers are lame
(and no offense taken :P): I don't see it necessary to learn to do so either, so I don't bother besides basic KK -> RRT. Plus, Pang Pang Air combo Rape > All. D:<