I hesitate to call this a feature request since I’m pretty sure this is a bug. Horizontal scroll of the mouse wheel should always scroll the window horizontally. It does so in the upper zone of the project window. It does so in the edit windows. It does so in other DAWs. Horizontal scroll should always scroll the mix console when the mouse is over the mix console, regardless of where the mouse is located in the mix console.
As it is, it’s nearly impossible to scroll the lower zone mix console. It’s hard to understand how Steinberg could have spent time on things like providing advanced coloring tools for channels, yet provided no easy way to scroll those exquisitely colored channels. The only explanation I can think of is that Steinberg is assuming users never have more than a handful of channels in their projects and never have a need to scroll the mix console. I can assure you that is an incorrect assumption.