I have a suggestion:

When rotating the canvas, the rectangular marquee tool aligns parallel to the canvas (not to the rotated view). I think this is quite unintuitive, for me at least. I think there should be an option in the Tools Option when the rectangular marquee is active so that the marquee will align to your current canvas view (however way it is rotated) and not on the canvas itself. I see the same problem with the Transform tool. When you have rotated your canvas, the transform tool aligns to the canvas, not on your current rotation angle. And even more strangely, if I make a square selection using the polygon selection tool that is aligned to my rotated canvas angle, when I use the transform tool, it is still aligned to the canvas not to my view. This is not very intuitive at all! Having also this option of rotated view reference in the transform tool, I think will be very useful. I havent seen this feature even in Photoshop or Clipstudio. If Krita had this, it will be a feature advantage of this software. What do you guys think?