I love colors as you know, but I agree it feels old!
I think it needs to be "flat" so to say (solid color no shading). And there must be some logic in the choice of colors and colors should be same for same project so every time you open one particular project it should use same color for the tabs every time you open that project.
Some kind of grouping of colors for when more than 1 project is open.
Maybe solving by having 2 color-tabs, first color for the Project (same color whole project) and the second color for the event sheet/layout tab.
Or I dunno. Well it needs to be changed.
Oh yes, now I figured it out. Border around the tabs that are part of same project. So you can see it is different project and also helps on which project is active if the border is different as well.