I feel that improved control systems could go a long way to making them more controllable. Look at RC aircraft, they used to take a lot of practice to fly and even when mastered required so much focus that they weren't useful for anything. But now drones practically fly themselves and instead of "flying" the drone, the pilot really just tells it where to go. The flight software figures out the rest.

There's no reason the same principles can't be applied to jet packs. Add a gyro or two, gps etc to give it the data it needs and the pilot should have a much easier time.

The more difficult to solve problem is with endurance. They are only good for 10s of seconds of powered flight.