If you don't play jazz piano as well as you'd like, take a moment and ask yourself "why?". Now make a list, either mentally or written down, of the top reasons you can think of.
You've probably listed things like "don't know enough chord voicings," "can't play fast enough," and "solos don't sound like real jazz." This could all be true, but it's not the main reason you don't play jazz as well as you want to.
The real reason is that you've never become fluent at improvising in a jazz context.
Here's the clincher: You don't become fluent by working on the "hard" stuff. Now I'm not saying that you shouldn't learn all your chord voicings, bebop vocabulary, etc. That is all very important. But what I am saying is that this alone will never make you a fluent player.
By fluency I mean the ease with which you can play, on an everyday basis. You sit down at the piano and play "Autumn Leaves." No problem. You have a good degree of rhythmic flexibility and you can play the melody, an accompaniment, and solo without struggling at each moment. This is fluency, just like with language.
The wonderful thing is that once you become fluent, you can expand your vocabulary as much as you want. You can even learn more vocabulary right from the beginning. But this is only if you're also working towards fluency.
Fluency comes from using your newfound vocabulary in many, many ways at each and every step of your development. Every day and every time you play. If you don't strive for fluency, you'll never be happy with your jazz piano playing.
Here are 10 ways to improve your piano improv skills. Good luck!