I love pixel perfect drawing… I mean I use it almost exclusively. Not to nitpick but it makes no sense to have the second color pixel perfect. Most of the time the second color becomes the value of the eraser. And when you erase using it. it is always a hassle because it always leaves artifacts behind. My suggestion is have a radio button that you can switch on or off that would allow you to use color zero as paint without pixel perfect drawing while at the same time using pixel perfect drawing on the other button. This would allow people to erase without artifacts while at the same time using pixel perfect drawing to draw with.
I think it would even make sense to always disable the pixel perfect when using RMB with transparency drawing, without having an option.
I guess that means that you like the idea and want to implement it?
Yes, if nobody else says that it makes sense to leave it as it is or to really add an option. I guess we will see when it’s changed. If nobody yells at me then it’s okay 
I thought about this a bit more and had to change my mind. I will add a separate eraser tool and this will not use pixel perfect drawing. For the normal paint tool pixel perfect drawing should be used when enabled, even when erasing.