409 karma · joined April 20, 2011
This sort of shallow thinking is representative of the designer, if we define designers very loosely and pathetically.
Bounceapp.com already does that URL thing you are talking about. I use it before I made Mocku.ps but I needed more precision i.e. tiled backgrounds, to better communicate designs to some clients.
Maybe I'm wrong but right or wrong isn't the point. Making people think and talk about something is.
I haven't looked into the cap height issue as much as you do but one thing that really bothers me and as a result the developer I work with is that Helvetica and Helvetica Neue have different top and bottom boundaries. So there are slight differences in text render on the Retina display.