#1 xml sitemap is causing server load. (A solution could be caching the sitemap and to show only last X posts not all. I have w3tc but still the server load is there. I don't realy want all the posts, I like only last 25)
#2 I'll like to see double quotes instead single quotes in the (robots, descriptions etc) meta tags;
#3 post seo box (add new post) needs redesign for smaller resolutions (1024*768).
#4 posibility to show only the seo title in the post editor interface (add new post) so that no meta description, google preview or other useless stuff is shown. Keep it minimal.
Your plugin is great but not all of us have dedicated servers and we like to keep everything to minimal.