In addition to allowing users to customize the order in which tools appear in the right-hand bar, it would be brilliant if Pixelmator Pro could figure that out for me. For example, after weeks of using the app, if I primarily use the Darken, Lighten, Saturate and Desaturate tools, but I never use the Type or Draw Shape tools in my workflows, the tools I mostly use would be listed (thus easier to select), while the tools I never use could be accessible via a "..." at the the bottom of the bar.
Say I always use Warp and Bump, but never Pinch and Twirl. Pinch and Twirl (since they're still a part of the Warp family of tools), could still be accessible by clicking once more on the Warp or Bump icons.