Some valid points but I'm not sure if I agree with the brush engine point. I don't think it's the most important feature of Photoshop to many, so not making that one right first is not that surprising.
Making a good brush engine is indeed a very hard problem, especially when you have undo history, high res canvases, layers, zoom etc. I just don't see it of such importance
Making a good brush engine is indeed a very hard problem, especially when you have undo history, high res canvases, layers, zoom etc. I just don't see it of such importance