PGP is better for those config/standardisation reasons, but Bitcoin's cryptography is arguably more secure. Awkward situation.
I'm sorry I still don't see how keeping your PGP over the years is easier/more convenient than storing a legacy btc addy for that purpose.
It's neither, but both aren't easy for different reasons
While your proposal would be a nice to have I don't see any point or reason in forcing people into it.
So the solution is already here. If you are more confident in keeping your PGP, you are already welcome to stake it. If you like BTC legacy more, stick with that.
My thinking is that high rank accounts are actually becoming a little more valuable now that it's more difficult to rank up. You need to put in some real work to do it, people would happily hack an account to cut that out. Imagine if a great poster had their Hero account's password hacked, and they couldn't recover their account because admin wasn't convinced their email wasn't hacked too?
Maybe a better idea is only to make keys part of high rank requirements, not to lock existing high rankers out of their accounts or something like that. To rank up, you need to register a key (PGP or Bitcoin), and you drop ranks until you do for existing high ranks.