What would be pretty nice is a strip along the front edge of the lever that isn't just a switch, but an analog sensor that as you etiher grip more of it (more fingers on it) or move a finger "down" the lever with a little pressure (but not enough to really engage the physical brakes yet) it would output an analog signal for controllers that have separate analog braking inputs for proportional braking.
It would take a small bit of getting used to, but would allow one to use purely regen braking with the same levers used for physical braking, first just a little, then more as sensor output increases, until regen is maxed out, and then if that's still not enough braking, one can continue applying the regen while then partially or fully engaging physical braking.
That's the kind of thing I'd like to do on CrazyBike2, which is 2WD, with independent front and rear throttles and brakes, and SB Cruiser, which is also 2WD but with independent left and right throttles but not yet independent brakes (will be when the rebuild is done). (and SBC has a separate mechanical brake on the front wheel).
Presently both also have a separate lever that's for the brakelight, so I can trigger that without triggering the regen, to help aggressive drivers figure out when to back off a bit
, because I haven't got any ebrake levers that are any good as mechanical levers, and I haven't made a reliable switch separate from the levers to do it; less time to learn the extra lever than deal with the reliability problems.
I've had some ideas on how to do the analog sensor, like adapting a sensor strip used on some musical instruments as a pitchbend strip, but I haven't pursued it with any design/testing yet. (dunno when that might happen; I don't yet have a pair of controllers that can do proportional braking).