I know this is an elaborate suggestion but the situation has occurred enough that it warrants proposing.
What if your unread feeds were deduplicated to further concentrate your new items?
Example that happened today:
I subscribe to Intel Press Releases and HackerNews. Somebody posts an Intel PR to HN, I see the item twice.
Other times, multiple people submit the same thing. Might as well only show it once.
You could even expand the concept to fuzzy deduping, so if 75% of a headline matches, consider it a repeat.
Ideally, the source story might list ‘also posted to:’ to link the duplicate posts. The dupes would be marked read when the source is read. You would be able to configure the setting per feed in the Intelligence Trainer.