I don't feel like my ability to interface with the computer is a major bottleneck for me. If I'm writing code, for example, my typing speed is really not a factor. Even typing this very short comment, I paused several times to think of how to phrase things.
It feels like a huge rate limiting factor for me. Even typing 2x as fast would be a phenomenal improvement.
Speaking is even worse though. Communicating verbally with other humans is frustratingly slow and inaccurate. A new non-verbal means to communicate would enable us to understand others faster and better. This would solve a lot of problems immediately that arise from our inability to understand others or the amount of time it takes to arrive at understanding.