Shape of Tent Floor

I don't have floor, sleep in bivy that has waterproof bottom

If the weather's nice I don't put up tarp at all, so the bivy provides protection against wet ground

If I didn't have bivy I'de probably use a 3 x 7 foot groundcloth the same way

If water drips from edges of tarp, it goes onto the ground rather than onto floor where it would collect

If there's a puddle or stream, a bathtub floor would provide some protection, but not total, need to avoid that with site selection

Other things unfortunately are never equal. In terms of designing a tent, floor shape is interconnected with the slope of the walls. So the way I see it, I can't compare floor plans without knowing the shape of the canopy. Now, if both of the shapes you show are in tents with nice steep walls ( yeah, sure), then I probably prefer the hexagonal shape, since whatever gear I have in the tent with me will be at the wide spot in the middle, rather than down by my feet (which is the only free space in the rectangular floor plan), and thus easier to reach.

#1 – this would be great for a tent where you don't require vestibules and where tent size/weight is to be made as efficient as possible.

#2 – Great if you want a roomy tent with vestibules that isn't meant to be the absolute most efficient tent for size weight. (likely the corners will go unused if you have vestibules for storing gear)

This all depends on what the tent design looks like though…I'm just basing all of this off the SMD Haven, Nemo Meta 2 (and similar tents) designs which are highly functional yet basic.