For 2016 I worked up some new covers for my books. I used the same art (my own) but reversed the priorities – putting the titles in the box and letting the art fill the cover. I'm thinking they're an improvement. At least I've eliminated that black outline around the text of A Summer in Amber that was problematical in the thumbnail images.
Everything I read about self-publishing says you need professionally designed covers. You should make your cover look like the covers of other, professionally designed books in your genre because people judge the quality of the book by the quality of its cover. I have to admit I do as well. That said, I can't say I'm all that impressed with many of the presumably professionally designed covers I see. Possibly because they all look alike. Since I'm not writing my stories to be just like other stories in their genre – I'm writing the stories I can't find to read – I think my covers should reflect their outlier nature. And since my stories are rather old fashioned, I think my covers should suggest that too. Which, at any rate, is my story, and I'm sticking with it. That, and the fact that my cover budget is $0, so cover design, as well as everything else, must be done in-house.