I did notice the similarities in the interface to Civ5 and I must say it didn't bother me one bit. The interface works, it's responsive and if you spend some time with it you notice some good refinements (click to skip animation is so awesome) that make the gameplay that much more enjoyable. My sincere opinion is that if it works don't try to change it just to be different.
Based on the demo, really, the only UI changes I'd like to see is perhaps a bit more feedback (maybe optional) on the city nameplates with respect to what is going on in that city (what's being built perhaps?) and in the future some visible indicator of enchantments cast on cities would be nice. I'm not going to complain either way.
As an aside, I discovered the demo yesterday on Steam, played it and promptly pre-ordered the game. I am a huge fan of MoM and this is the closest game to that experience I've had in a long while. I hope you guys plan to develop it further in the future (expansions, dlc) to add more fun elements to the game (heroes and artifacts come to mind). In any case, great job! Looking forward to release day tomorrow.