> - lots of posts include iframes, or content that only makes sense with JS enabled
These are the fault of broken RSS feed generators. The RSS feed should contain a textual summary of the article.
> - if I want to follow any link I get kicked back out to a bloated web page
This is working as intended and not an issue. I don't think any alternatives would make sense.
> - there's no pagination mechanism, or way for a client to ask for "all posts since last Friday". If you want your feed to always have all posts available, you need to include the entirety of your archive in every feed response.
Agree that this sucks.
> - XML
Really?