Would be great to see a M/S (Middle/Sides) option added to the otherwise excellent Pro EQ, so it could be set to impact just one or other, rather than the whole signal.
Whilst this can be achieved with 2 Mixtools and a Splitter, it'd be much more straightforward and accessible to have it within the EQ itself.
Obviously, it should default to 'All', rather than Middle or Sides, so that there's no impact to existing workflows.
For an example of this already implemented, check out the Waves H-EQ. It can toggle between Stereo and M/S modes.