CDNs - Make sure you add a Cache Control (max-age) header to your CDN sync. This doesn't happen automatically through most syncing mechanisms. Helps you save on those pesky HTTP requests that cost $$$.
Gzip - Do not gzip images. It's not worth it. For HTML/JS - YES!
Javascript - If you have ads, definitely load them asynchronously (they go through multiple servers and take ages..). This is really important as you want your document.ready to fire asap so that your page is usable.
POST - Always redirect after a post request to prevent reloads causing re-submits.
Forms - always have a submit button for accessibility.
Usability - Try using your site with a screen reader, don't neglect vision impaired people. (there are apparently a lot of them!)
data-x attributes will destroy your W3C validator checks. Use them if that's not important. (sometimes it just is...)
For external scripts that use document.write go take a look at Writecapture. It's a document.write override which will make your external scripts asynchronous. (https://github.com/iamnoah/writeCapture)
I don't see why counts and pagination are such a big deal. Have done them correctly multiple times. Faceting might be hard though ;) It's a useful usability feature to show counts. (or atleast show counts when there is nothing - i.e. a zero count)
Those are the ones that I could think of right now. :) Great article, some good points in there!