I do like the look of the new S5...very "clean" looking. Simple graphics, but the color scheme is carried across the bike...wheels, saddle, tape, graphics...very sharply dressed in a tuxedo kind of way :)
I'll wait for the specs to come out, but it does look like a revision vs. a "new" design. I see there are Conti tires there....that bodes well for taller tires, but I'd still like to see room for GP4000s 700x25's for us bigger guys and folks looking for the advantages of wider tires. No, I'd not be looking for 28's on an S-series frame, but Conti 25's would be nice.
Not quite enough to get me off my S2 yet (though the compliance of the S3 with only a minimal aero penalty vs. the S5 makes that frame a bit more tempting, but that's only because of my current riding style and needs).... but of course, if this Clyde butt were given an S5, I wouldn't complain and I'd ride it like I stole it :)