Interesting. I use both C12 and Wavelab 11. I don’t see Wavelab as more “modern” than Cubase. Wavelab offers the light and dark modes. Actually, I think I like the overall look of Cubase over Wavelab. I’m specifically thinking of Wavelabs Montage, and the wave editor compared to the Cubase Project page and Cubase Sample editor. I do most editing of samples in Wavelab, however that is mostly from habit.
What specifically looks old in C12?