Given current conditions, balancing this new flying thing will be tough. The idea of actually putting it in the wide open, even with its speed, gives it a long time of exposure to human fire. Maybe if played with later jumps into open area battles so it's not focused, I can see it not being so soft. Also, perhaps the potential for circular maneuvers would be nice. I'd like to see it be able to do a dive to a wall and latch on. Overall I'm trying to say that I don't see any MAJOR purpose or fun -- as of yet -- in a flying alien unless one of its key points is rather extreme elusiveness. You can look at airborne marauders from Tremulous as a reason for this.
But balance comes later, as was mentioned. Personally, I think the design is excellent and I like the idea in general of a flying form.
P.S. Everytime you fuck with the baslick, mother nature strikes individual cute baby animals with a multitude of focused natural disasters, so fuck off.