As I've been saying for years, "identd (identification protocol) is pointless and potentially dangerous." At least one of my readers (yes, you) will immediately recognize this analysis...
(By the way, I think there's one point you missed on the issue of its pointlessness: These days, just about every system that one might reasonably expect to provide a trustworthy and useful ident response -- except within enterprises -- is behind NAT anyway, and ident doesn't work through NAT to my knowledge. If anyone knows of a firewall that does properly forward ident across NAT, please let me know -- I'm curious.)