Now that we can literally "see" almost every tornado from radar we know what we have now. Furthermore, with the ready availability of cell phone cameras and whatnot we have seen a drastic increase in weak tornadoes reported. Let's face it, you all watch the chases in the south. You tend to get a whole lot of three things:
Rain wrapped
Night time
Trees
At least you can see in the plains so historically it might have seemed obvious to us that was tornado alley. I don't doubt a shift to the SE so don't get me wrong but I wonder to the extent that this has always been the case. There have been some epic tornado outbreaks in the south long before climate change was involved. I am thinking of a few oldies like the April 24, 1908 outbreak and the Enigma Outbreak just to name a couple.