Having the unfortunate experience of shooting commercially cast bullets that had bullet lube made from blue crayons, or some other similar hard wax, I can definitively state that NRA 50/50 is a far superior lube for handgun bullets.
As for the capacity (size, depth, shape and number) of lube grooves, perhaps the old Keith designs didn’t catch up with the improved lubes such as 50/50. But at least we have the ability to design custom molds that hold less bullet lubricating material OR simply not fill every available lube groove if we choose.
My most often utilized 38 Special wadcutter bullet is a Accurate 36-154W, which has only 2 lube grooves and works just fine. My MP hollowpoint mold has two lube grooves but they are rather shallow and that also works. Traditional Keith bullet styles were likely set in stone just a little too soon. And similar to CZ’s comments, if you powder coat, this is about as relevant as discussing the best buggy whip.