Only reason why Samsung added is cause it's in stock Android... not sure if they will copy OpenCanvas fully. One thing I wish they copy is the new floating window in stock Android.Yes I agree with you 50/50 or 70/30 is optimal but once in a while I like to change it up. 100% Samsung can definitely do it so hopefully it comes down the road with an update fingers crossed.
It looks so much cleaner than how Samsung has it now... I use pop-up window feature often and it's been awhile since they made changes to it.