"Context"? Don't you mean "design"? I regard the fact that I don't have to view most blogs in their original look one of the best features of RSS, saves me from activating Readability all the time.
There's a Feed view, which is what you're referring to, as well as an Original view. There is also a Story view, which shows you the click-through of the story, which is convenient for some feeds, like Hacker News.
The majority of sites that I personally subscribe to are individual writers. I want to read their writing in the exact format that they intended it to be read. Daring Fireball comes to mind.
I'm aware of the different NewsBlur features, I'm not saying that I don't like the software (if only it didn't have such a huge stack needed to run it…). And it's great that I can choose. I just wanted to state where I stand in the content vs. presentation issue. Even most a-list bloggers often have pretty unreadable, if pretty, layouts. I'd include DF there, by the way…
I'm also not quite sure about the ad argument, i.e that you're eliminating the revenue of bloggers. The feeds themselves can contain ads, there's the compromise of abstracted posts in feeds, and then there's the distinct possibility that users who are proficient enough to use RSS also have something like AdBlock installed. Personally, I see more ads in feeds than on actual sites, due to dedicated feed readers not blocking ads, and the relative low level of annoyance doesn't prompt me to use a filtering proxy for that - never mind that I could on mobile devices…
One thing that I dislike about reading in RSS readers is that it's getting somewhat more common to include interactive things in blog posts, and I'd like to see those (and encourage that trend). Things like having a running example of a code snippet, or interactive statistics/data-viz stuff. Sometimes JS/canvas/SVG stuff works in Google Reader, but often it's broken, and non-browser-based readers usually don't even try.
Yes, that is a pretty hard problem, i.e. how do you distinguish between JavaScript highlighting a source snippet and doing something that messes up your presentation? In the end, I don't think this would be worth the effort. Keep the feed reader simple enough, the real post is usually just a keypress away. My usage pattern in Google Reader is just pressing "v" to open a tab with that post for later referral (it's easy enough to modify firefox or chrome to do that in the background).
Of course, if you have total control over your RSS generation and feel particularly perfectionist, you could always have some minimalistic features present in your feed, probably similar to your print CSS version. Bold and italic for syntax highlighting, for example.
