I suspect many people only use the sunroof's tilt function (/position) and use it as a vent rather than opening it up.

If that's true, then Porsche (or someone) should make a small 'vent' the performs the same function as 'tilt' and weighs 1/10 of the normal sunroof's weight.

Then we can have our cake & eat it too.

It could be a bad assumption, but let's find out?!