So, after we've all graduated to using microcontent clients to navigate through websites, people whose weblogs are primarily read through their RSS feeds are going to get upset that they've lost so much control over the appearance and branding of their sites.
It seems like what we need is an RSS reader that understands XSLT, and a simple way to either easily create simple XSLT sheets for RSS feeds, or to convert HTML CSS sheets into comparable XSLT sheets. Then my weblog's posts in your aggregator would get an appearance applied to them in whatever way I specified. Of course, another needed element is for everyone using Movable Type as their publishing system to modify the default RSS templates to use MTEntryBody instead of MTEntryExcerpt so that you get the full text of your post in the RSS feed.
To this end, I've pinged the LazyWeb site, so that someone can get busy either building this or telling me where it exists already. Nice work by Maciej in integrating his Latent Semantic Indexing work there, I hadn't noticed it before. Seems like an ideal venue for it.