There are people who have said that "an update to the Pencil is imminent"...that was over a year ago. They're still waiting. Unless the current Apple Pencil doesn't meet your needs, there is no reason to wait. There is so much FUD (Fear, Uncertainty, and Doubt) surrounding the decision to buy Apple products that some people become paralyzed into perpetually waiting.
Examine what is currently available, determine how well it suits your needs, if it does, shop for a good price, buy it, and enjoy. Don't let the "fear of missing out" of some potentially new and better thing cause you to miss out now.
Because frankly, some of the stuff we wait for is pretty goofy. Nobody, absolutely nobody, looked at the 12.9 iPad Pro when it was first released and said, "ugh, the screen refresh is so annoying. It is so blurry. I'm holding out for a model that offers 120Hz refresh rate".