As I tend to do all my mixing in Renoise also, I absolutely love having the Spectrum and Phase meter available, built in. However, I often find the Spectrum a little difficult to use because on my 1920x1200 monitor it stretches out far too wide to really be useful. Peaks become hard to see (especially in the bass frequencies) because they’re displayed so wide. To narrow down the spectrum I have the Phase meter opened, but it’s still a good 80% the width of the screen, which really limits its ease of use.
What about simply allowing the user to have both Scope view and Spectrum view open at the same time at the top. This would half the width of the Spectrum and make it far easier to read.