* blog software dropping JS-dependent elements into the feed
* leaving out formatting (e.g. leaving line breaks)
* software updates etc triggering entries to be republished
All of these are IMHO "faults" in the publishing software.
A clearer standard for what you actually put into a feed (formatting) and potentially permissions for caching of e.g. podcast episodes would be helpful, if it were actually enforced (e.g. by clients being strict and dropping non-conforming contents). There clearly is potential for improvement, but I haven't seen any strong candidates that could do better, + they'll have a hard time gaining momentum vs the "good enough" right now.
(P.S.: if someone disagrees and has a good suggestion for something better, please tell us and don't just downvote)