On one hand, for my client, making URLs sexy again by making it short and readable is desirable, tho on the other hand I don't want to remove those addresses in case the client domain gets nuked and those shared across the net sexy links won't mean anything anymore / the user can't grab the address to put it on another client.

So sticking with unsexy addresses in favor of ease of interoperability/sharing + in case of client/project nuke.