I've discovered a HUGE performance increase opportunity! All filters ignore artboards and use hidden "real document size" instead. This makes photoshop to technically redraw all the hidden pixels. Situation: you have 6-10 artboards with for ex. layout variations of some design (print, banner outdoor, UI, etc) each artboard has ~50-100 smart objects with some filters/raster masks/of filters. As a result, it becomes almost impossible to edit anything because PS has to redraw all the useless space hidden by artboard bounds and it takes ages!
I think it's possible to change how artboards are rendered. Something will definitely break with that change but the win from that will be VERY big.
As an alternative, I think there should be a switch in the settings: "Use old Artboards" which will make all the scripts and plugins backwards compatible. Plus you can create a new scripting API for the new methods instead of replacing old ones.
Imagine even when you create a solid colour it is not actually cropped by the artboards under the hood. Basically, artboards are acting like simple rectangular vector masks but regular vector mask defines bounds.