The comment problem is template-settable -- you don't need to go to the generic Blogger comments form. Mind you, the documentation is a little on the opaque side, and one really needs to be interested enough to go through all of the tags. The CAPTCHA time-out issue is a bit of a problem for longer comments for us slow typists (or, I suppose, for deliberate thinkers), and the only real answer for including background images is to base64-encode them in data URI on the stylesheet -- the browser will give up before getting them from the associated Picassa album about half the time if you use a URL as a src. Since the stylesheet is part of the page (not cached), that means the images need to be kept small -- good discipline, perhaps, but it ought to be a choice.

The only real missing link I've run across is the ability to create honest-to-goodness static content, something that won't show up in the blog archive -- although there are values available in the latest template tagset that indicate that something of the sort is at least under consideration. (At the moment, there is no way to intercept entry generation in the archive menu-writing loop, although you can use content tagging to rip a full-length or abstracted entry out of the normal page run.)