I am glad you brought this up, Frank! 
I have been all over both sides of the street on this one. At one point I was all about slotted rods. But, things were a little different at the time. That was back when Sonor wasn't stingy with memory locks and the memory locks we also slotted. Then the square headed rods started showing up on lower end Sonor drums and crept their way up through the lines until it's all square headed now.
When I worked at DCP, I had a list of this I was going to present to Shane but I vacated (evacuated) the north before the chilly nights turned brutal. At any rate, one thing on my list was to offer rod conversion kits. The basic idea would be to have everything on hand for someone to convert their SQ2/ProLite/SQ1/Vintage (or whatever) drum or drums to slotted rods. In and of itself it doesn't seem like the smartest of ideas, as there would potentially be a very limited market for such a thing.
But, couple that idea with another dumb idea of ordering all SQ2s that would be for the store's inventory with square rods, but have the slotted on hand for an easy changeout and it makes a little more sense.
Add those two dumbass ideas to a page full of other dumbass ideas I had and we would have actually had a host of things that could be configured to the customer's liking on the spot; and in doing that would have elevated things upward one more notch. It's one of those things where one or two elements of something in and of themselves really don't seem smart, but when you look at the whole package it makes much better sense. Just like you don't eat ingredients to your favorite cookies one by one. You mix them up and then eat it.