Paint has always been a rather useless app, only good for fun as a kid. On a contrary Paint.Net is awesomely practical. Having a cross-platform Paint.Net implementation - this would be really cool.
Nowadays I reach for Krita for all my image manipulation needs
It is not nearly as intuitive as Paint.Net is. Paint.Net UX is perfect, it really is what Paint should be. On Linux there is Pinta which is a slightly-worse port o Paint.Net.
4chan users beg to differ...
Paint is all one needs for basic cropping, cut/pasting, highlighting, drawing arrows, superimposing text and basic image manipulation. I think that this level of simplicity is admirable, because it means the application takes a second to boot so it doesn't break your flow when you're trying to get other things done.
Why on earth would you remake one of the shittiest paint applications ever released?
Windows 7 version of paint on the other hand is better than most paint like applications on Linux so if they made that version cross platform then we could finally have a decent simple paint program everywhere.