> And it's not like the urls are rememberable anyway

They're what everyone sees, when a link is shared. It's a fundamental part of the user experience, for a service like this. As stupid as it is, I would be a bit embarrassed to share a link with "dump" in it. Dump.ty is fine/great.

> adding the extra route seems more "future-proof".

I'd claim this is a separate issue. "routing" isn't real, after all, it's just string matching. Most/all routers have regex match options that might take some ns longer. You're free to do whatever you want in the future, trivially so if you make sure whatever future path doesn't look like an ID.

The $0.01 solution is to use /d/