Do you have ideas to make Krita into an even better program? Check out this manual page on making feature requests first!
You should then discuss your ideas on the Forum or Krita Artists to get feedback from other Krita users. When your ideas have ripened, it’s time to make a feature request (a wish) in Krita’s issue tracker.
Please keep in mind that it may take years before a feature is implemented: there are a lot of things that could be done, but only a relatively tiny team of developers. You can help speed this up a bit by working with the developers on additional details such as the graphical interface, as well as providing links to relevant resources. Here is an example of a good feature proposal write-up.