I purchased Affinity Photo pretty recently as an Adobe Photoshop refugee. I'm hoping to have some minor annoyances fixed:
Crop tool: It needs to use a hairline for the cropping rectangle so you can crop to exact pixels, and it needs to snap to object boundaries, so you can quickly crop the canvas to fit what you have on there.
Zoom: The zoom keeps changing back to fitting the window all the time. This is irritating when you want the zoom to keep to whole steps (25%, 50%, 100%, 200%, ...)
These might not be super important if all you do all day is edit photos, but it is pretty important for pixel design work, and I did a significant amount of that in Photoshop.