Tim Berners Lee, the creator of the Web and of URLs, wrote some time ago that he regretted the double slash in URLs, saying that one would suffice.
It went a little further than that, I think the scheme would have been: http:/com/ycombinator/news/item?id=796434
People would just end up using a different separator after the DNS part, and you'd be back where you started (just with big-endian domain names).