In essence, I should be able to customize the actions highlighted in red below. I'd like to be able to set the top left corner to snap to the left third of the screen and the bottom right corner to snap to the left two thirds of the screen and the inverse for the right side corners. My apologies if this has already been requested.
This would definitely be nice... A workaround (but not as nice in my opinion) is to disable a given edge and create a snap area that mimics it, but it's tricky to guess the exact dimensions and position of the area to get the same behavior. I guess I'll have to continue with snap areas for now in lieu of this feature.
Edit: one reason it's not as nice is on multi-monitor setups... you have to define the new snap area on each monitor to get the same effect as the default edge snapping.