My biggest beef with Posterous's design is that they direct me to their front page too often. When I'm logged in, just take me to my blogs. How many times have I ever seen the front page of blogger?
I hear you. We've got some cool concepts on a dashboard coming... we literally just grew the team by 50% people (2 great engineers) in the last couple of weeks, so we hope to be putting out a lot more good stuff for you.
Mine is that with ordinary text emails, it will make very ugly HTML code, like putting hard breaks instead of proper HTML paragraphs (even though it shouldn't be that hard to do, with properly formatted emails). I wouldn't care about that much, but when somebody looks at the site with unexpectedly large fonts (and not even very large, with common 67 columns paragraphs and default posterous themes, it happens quite too often), the browser will break lines sooner than the hard break, and then again at the next line, after few characters. That sort of sucks.