A last note, before I go offline:
It already takes time to find a usable EQ plugin when e.g. using
Qtractor or Ardour. Proprietary DAWs usually provide relatively usable
EQs by default.
So IMO it might be a good idea to add by default that kind of EQ to the
Linux DAW's mixers, we will find on good analog mixing consoles, resp.
something similar.