Maybe this is a stupid question but, why the dependency to a browser? I see the advantages but it also adds complexity.

With a feed reader the most important is to read the feeds.

1. Gimme the headline and link to source.
2. Perhaps some excerpt too.
3. Probably the picture(s) as well.
4. Download the downloadable media as long as there is wlan available.
5. Full content? Well, yes although I can perhaps wait or just download via data connection if it's really urgent.
6. Real HTML formatting while offline? Well, If I really want the real page I can visit it with the real browser.