From what I read from you elsewhere in these comments, though, subscribing to an RSS feed in Prismatic does not (currently) mean you will see 100% of the content in them - correct?
... If you are indeed changing it to include 100% of the feeds of my choosing, that's great to hear.
What I ALWAYS want + 'a little extra I might like' is something I can appreciate.
Right on all counts. On the upside, we're smarter than an RSS reader for high-volume feeds currently, and sort things based on how much we think you'll like them (based on topics, social information, and more) rather than just by time. Support for the 100%-of-feed use case is in the works, stay tuned.
If by 'that feature' you mean the sort by perceived importance vs. time, I hope they make that possible to configure.
If you instead mean the suggestion of additional content into your feed - that's really the core point of Prismatic. I wouldn't expect to see that configurable / given an "off" switch ever. In fact, I'm pretty sure that's how they'll monetize the product - slipping in pay-for-placement content that's relevant to what you're reading.
If it can I could never find it. I tried the service out twice and both times found it to try and show me a lot of stuff I didn't want to see and never improved on that front.