I'd like to throw my hat into this ring.
Daniel has some very interesting points and it's shame they seem to keep being stomped on.
The interface for mc hasn't changed in so long, the whole thing is looking very 'long in the tooth' - Most people would be hard pressed to 'see' anything different between the last 5 or 6 versions. I know function is more important than form and there's no doubt you have been working very hard on adding features and improving others pretty much constantly over many years and for that I and many others are very grateful so please don't thing I'm complaining or grumbling.
Interface is very important though, especially when trying to attract new users. Look at the web and apps and how much they have changed over the just the last 5 years. I know change just for change sake is sometimes pointless, but not always, it refreshes things, helps it compete in an ever changing market.
I'm not going to go into specifics here, but there are countless UX professionals who could help make improvements with the interface/user experience. Or is there a economic issue? Are funds too limited to draft in any more staff, even temporarily?