It just happens that the use case for web developers overlaps and that is what folks seem to care about around here. :-)
I don't know how much bigger that is than your vision, since I can only guess what your vision is. :-) I can guess based on your design, that until now you haven't cared much about people using localtunnel for anything except dev testing.
If I were starting from scratch today, I'd base off websockets instead of the HTTP chunked encoding as I did, but other than that I have been very happy with it.