The hardware is not the problem. The CC121 is just a very simple MIDI-controller. The buttons send note on/off, the fader pitch bend values and the encoders CCs. That’s it. This works as expected so there is no need to update something here.
The mapping in the software is the problem. It would be pretty easy to optionally swap two CCs to reflect the eq’s screen layout or to scale the CC values to customize encoder speed. The REAPER extension shows how simple this is (including source code).
AFAIK Steinberg and not Yamaha is responsible for the glue between the controller and Cubendo (aka ‘CC121 tools’). So in theory there is hope for an updated version but I wouldn’t hold my breath.