Both UVS look very nice and maybe if we didn't already had the first one some things wouldn't make a difference. I understand what you say about this UVS to be more friendly on other applications... on my eyes the perfect solution is in the between (as a poser user anyway I can't talk for other applications)

Comparing the two of them there are things I like on both
I like the way the new one is cut but would prefer a stitched version like V3 and it looks like it could happen without huge space waste, secondary parts could go with the body. this would be a very poser friendly and also easier even for not advanced texture makers to use.
the lips are very very tricky to match in photoshop if they are unattached,  the transition becomes sharp and the new textures show that.
eyes are better mapped also on the new one (don't know if the iris is separated from eyes white, this would also give sharp edges)
also lashes and eyebrow should have a separate map for a poser friendly version, each of them,  and that because many people don't use transparency for the eyebrows
I'm sure anyway that both versions are super fine already and very easy to use, they can give great results

My FreeStuff