New here, saw the new handle design and wondered what buttons, switches, HATs you were thinking of making available?
You have already removed the need for multiple analogue sticks just with this throttle!
Looking at SC though, a small analogue stick for gimbal aiming would be a nice addition - https://www.sparkfun.com/products/9032
Is a nice example of what would be available. The price is reasonable too though I am not sure what prices you will be able to get when buying bulk!
I can also see a 4-way dpad or arrangement of buttons (spacing would make this a pain - the joys of not ever having to deal with ergonomics in my designs!) for moving around power with modifier buttons being useful as well.
Of course, that being said, everything has a cost attached to it. Both a parts cost and a time cost!
Just wanted to make a few suggestions for what is looking to be a very interesting project! (May build one if it doesn't cost the earth for shipping to South Africa for the parts I can't source locally)