I own Yuneec E-GO Electric Skateboard. My friend rides Booster Board. I wish these things were hackable so people can write their own control algorithms. Couple ideas:
1. Use mobile phone accelerometer as an additional sensor to optimize motors' torque during turns.
2. Use mobile phone GPS. If you have a regular commute your board may know that you are approaching an intersection or a stop. It could also know in advance an elevation profile of your route and adjust accordingly. The same information could be used to more accurately estimate remaining battery.
3. Learning your individual riding style and adjusting acceleration/braking patterns to it.