It seems the period of time, at least on my system, between entering a bad password for sudo and getting a "Sorry, try again." prompt is between 1 and 2 seconds. Probably closer to 1. Is this too long?
For me personally, yes. I can't speak for anyone else.
Anyway, if you think this is a feature everyone would benefit from then you should use bugzilla to submit an RFE (Request For Enhancement) against dnf.
Will do, thanks!
-- Ds