Is it time to enable checksums by default, and give initdb a switch to turn it off instead?
I keep running into situations where people haven't enabled it, because (a) they didn't know about it, or (b) their packaging system ran initdb for them so they didn't even know they could. And of course they usually figure this out once the db has enough data and traffic that the only way to fix it is to set up something like slony/bucardo/pglogical and a whole new server to deal with it.. (Which is something that would also be good to fix -- but having the default changed would be useful as well)