Mr. Vestberg, why don't you go and talk to a field-engineer about what's going to happen to your precious terrestrial base-stations days, if not hours, after the field crew moves on. Unless you happen to have an armed platoon guarding it, well don't be surprised when it's been sold/traded as scrap. At least with Loon, you don't have that worry. Frankly, were I in the locals shoes, I'd do the same.
As for frequencies/bandwidth, well that's where Software-Defined Radio fits in. Then it's a matter of the Loon knowing it's coordinates to use set frequencies. Heck, add directionality to the mix (I would) and that mitigates bleed-over where you have antagonistic nations involved. In any case, we've tolerated each nation going their own way on how spectrum is allocated. When will it be time to have some type of common allocations. ITU? Might be your balliwick.
The rest, is pretty dirt simple. What isn't is what materials are going to be used especially for a smart-skin (solar energy), storage cells (I'd use super-capacitors), yada yada. Nice try at FUD, but if I can figure this out, don'tcha think the real engineers over at Google haven't already got this in the pipeline.
One final thought. Loon would be awfully useful in instrumenting the planet. All that weather/climate stuff.