Unfortunately you do put weight on forwards controls. While riding you will at some point need to shift your weight forward to your feet and off your ass. Because the action needed to activate the shifter will be so minimal, I think at some point an unintended shift is inevitable.
This site may be full of boring old ideas, it's also those boring old ideas that have been proven time and again for over 100 years.
I'm all for new, and think you may be able to figure out a way to make this work (Teazer was headed in the right direction) but as it sits I see problems. Keep at it and find a way to make it work if you're dead set on it. I don't know of a single innovation in any field that was dead on perfect on the first go round.