Sorry. But still, then intent was to be user-friendly (right?), and a side effect was to make it possible to renumber without anyone noticing.

No. DNS was created because the management of everyone editing and downloading one huge file was just falling apart. The Arpanet always used names instead of numbers. Moving hosts around was always possible. CIDR doesn't affect that fact that if nntp.com switches, say, to BBN Planet then I will have to get a new address. CIDR just says you can route based on smaller/larger granularity than IP Network Address classes.

That's the connection between DNS and routing, and it's why using names instead of numbers is Good.

There is no connection. Using names instead of numbers is good. It does bring up an interesting philosophical question about where the True Name really is. And how DNS must be part of your TCB unless/until you have end-to-end mutual authentication. /r$