Once you try programming MIDI performances in Cubase key editor using VST Expression maps, you'll realize how much easier it is than going through the task of setting key switches (sometimes a few of them plus another controller on its own lane, all this for a single note) in other sequencers.
Regarding Reaper. I made an FR on Reaper's forum to make the lower area of the MIDI editor more accessible by splitting it with a separator (http://forum.cockos.com/showthread.php?p=621518).The official FR is here: http://forum.cockos.com/project.php?issueid=3132
So far 32 people voted for this FR and it got the priority rating of 4.
Even if it's implemented, it will only allow for a fraction of features Cubase's VST Expression has.