The issue of control with newsfeeds and RSS has been on my mind a lot the last year or so.
RSS and Atom are great as a protocol, but where things break down for me is in discovery, filtering, and selection of content.
There's a few traditional RSS/Atom readers I like, because I have complete control over the feeds I monitor. The problem with this is that then I have complete control over the feeds, and have no way to be alerted to content I might have otherwise missed. I think this is part of the "unread feed overload" problem mentioned by some others, that I just a firehose of feeds at me, with no prioritization of content.
The other end are more curated things, like Feedly. This is great, because I get alerted to things that are popular, but they're very centralized, and it seems like the more you get curation, the less often you're able to customize your feeds. Also, for whatever reason, with the curated systems, it seems like you kind of get the same things over and over again from different systems, like there's a set of feeds they all dip into and don't deviate from.
This is my ideal in an RSS/Atom reader (not saying it's realistic):
1. Open source
2. Good UI
3. Can import and export using OPML or other similar standard open format
4. Cross-platform, between desktop and mobile
5. Decentralized feed recommendation
The last part is where things go a little off the beaten path, which is that it would be nice to have some way to get introduced to popular content without it going through some centralized service, like a recommendation system that's decentralized.