Every announcement uses different terminology, different reward tables and different download links. Half the arguments here are people discovering some detail that should have been obvious before launch.

Would a standard announcement form help, or would it only make copy-paste coins easier?

A form alone would be cosmetic. A useful standard would emit the parameter file, source snapshot, build manifest and checksums from the same inputs.

Require a public countdown and lock the parameters before it begins. If the creator can change the reward or premine after people arrive, the template proves nothing.

It would at least make omissions visible. A blank premine field tells you more than three pages of marketing copy.