There is a new UI in the works, I have seen screen shots and a walk through. I'm not sure what the release date is but it did look beautiful. There was a vote on the styles a month or two ago in the community but I can't find it anymore.
The new look and feel for Marketo is coming out in the near future from what I heard. There are currently some users that are in the Beta testing for that. If you are interested you should reach out to your CSM, they should be able to let you know if that is still open or not. I think it's as simple as completing a Beta agreement.
I'm excited to see the new interface, it's going to be refreshing!
I'm also eagerly awaiting this! Given that it was announced at last year's Marketo Summit, I'm pretty sure they'll want it to be launched before this year's Summit!