I am a little disappointed that VW hasn't came up with some type of fix for this. It is obviously a design flaw due to the number of occurrences, and there should be some type of fix that corrects this so that it is a very isolated issue. I don't believe this is VW's first "panoramic roof", so there is probably some data that indicates it CAN be solved.
Regarding lemon laws, I think you have to have three occurrences before you can start to file a claim. It is after repairs/modification prove to not have solved the problem, then you have circumstances that provide proof that something is indeed wrong with you car.
Work with the dealer on the lemon law aspect, as from a dealer standpoint, they want a happy customer and they have some
skin in the game to get VW to buy back your vehicle. I have seen this work well with a Lincoln dealer who had a leaking sunroof that went through re-sealing the sunroof, replacing all the gaskets around the sunroof, and as a last resort, replacing the gaskets AND the sunroof...to no avail. The dealer helped file the paperwork, Lincoln bought the vehicle back.