That looks nice, very warm! It cheats a bit over the actual functional complexity we need to expose in the UI, but that's totally OK for a visual mockup. You might want to check out the functional mockups we did for the upcoming launcher redesign, since it will add more stuff like chat, server management, etc. https://trello.com/c/IVEnTXCe/701-redesign-launcher
Overall I don't know that we want to go that far into a game-like look for the UI, but it is thought-provoking, Pixel-boy, Bilou and I will definitely have an interesting discussion about it and we might come up with our own proposal somewhere in the middle. In any event, I really want to see what you'll come up with for the project editor window itself :)