It would probably look nicer with actual lenses, even if the lenses are just clear glass for people who don't need corrective lenses. I imagine it'd also help if the design was symmetrical, rather than having a bulge on one side that reminds everybody else they're constantly being recorded.
Of course, I also imagine the Glass design team tested those options, and decided to go with the current iteration for a reason.
Just my three cents - but I'd hate 'zero' lenses on Glass. My eyesight is just fine, and I find glasses to be huge hassle and generally annoying, having pieces of glass that just sit there without a reason would be very annoying.
Surely they could provide it as an option. Most of the glass photos I've seen have had no actual glass (ha), while some of them had sunglass lenses or actual lenses. I'm sure there will be options to suit your tastes.
I'm farsighted and I've been using glasses since I was ten. You get used to it. To the extend that they completely disappear from your mind if they're good glasses. Titanium frames are something incredibly awesome.
I wouldn't want 'zero' lenses either, they obstruct your vision by getting dirty and having light reflexes etc and also are an additional risk to your eyes in case of accidents.
Of course, I also imagine the Glass design team tested those options, and decided to go with the current iteration for a reason.