You echo my sentiments exactly on the floors. 800mm hydrostatic head equates to 1 psi, if I've done my math correctly, and these coatings on the floor of these tents do get wear and tear over time, reducing their effectiveness in keeping water out.
What's the point of having a floor if it leaks? A 200lb person (or even much less) kneeling with most of their weight on both knees, and especially if on only one knee, will exert many times the rating of the floor and some of these tents.
I think I could live with the 2500mm hydrostatic head floor in the Easton Kilo 1P, but even with that one, I'd be concerned. I like that Easton has taken a little different tact, due to it's own technology of carbon poles that don't have heavy shockcords in them. This lets them produce a UL tent, with the weight taken out of the pole and not so much out of the fabrics and fabric floor coating, resulting in probably a stronger, more protective shelter overall.
Just wish one of these companies would 'put it all together' with a lightweight carbon pole, 5000mm hydrostatic head floor with 6" bathtub floor walls and about 10-12" of very breathable 10 denier fabric above that to a roof of noseeum and a side entrance design where the vestibule truly protects the tent door opening.
Is that really too much to ask in a freestanding or nearly freestanding shelter? Maybe it is...
I'll report back when I hear the hydrostatic head pressure number for the foor in the Nemo Obi Elite 1P.