Well the theme is not that bad in my opinion, I just would change some colors (e.g. sidebar titles). Maybe the background should not be that dark but thats a question of taste. If you don't want to make a single screenshot (cover like) for every post you could also put the thumbnails that you have in the posts into the summary so they shoo up on the main page too. Also you could remove the meta widget in the sidebar. Thats just some of the changes I would do. I hope I could help you.
