Steinberg,
Look, I know programmers & users think a bit different, for good reason. But after seeing how long people have asked for better midi editing tools, I’m wondering if Steinberg is listening to this. Or maybe doesn’t know how to do it. If that’s the case, I have an answer:
Look at everything Cableguys are doing. Hire them to design you some new curve tools if you must. Their tools are modern, fast and easy to use, and look good (for those who care). Several companies already use those mechanisms for drawing. So it’s not inventing a new concept. You already have the answers in front of you. Just do it. 
Thanks,
Sean