Crowdfunding is just another way for the community to interface with the free market. My friends and I were really happy with the quality of both DOS and DOS2 and would like to have an opportunity to further support Larian.
That being said, it is very tricky and as Stabbey pointed out, perception can be against you if your move can be seen as opportunistic. As far as the specific suggestion of an endless dungeon - I don't think that works but just my opinion.
I'd be all for DLC and I wouldn't mind crowdfunding it but my friends and I might be outliers and I think Larian has such a good reputation so far that any change to their current formula could be bad. Interesting thought though!
