Right, I just wanted to bring some awareness to this issue as I've seen it denied before. I am not using the beta, but I tried reticking the boxes anyway. Same result as before. HD textures do not load without the ESPs.
I have the HighResTexturePack BSAs enabled under archives in Mod Organizer, but their textures do not actually load in Skyrim if I do not also enable their associated ESPs. Below are two screenshots of the side of a building near Whiterun. In the first screenshot the ESPs are disabled as suggested by Mod Organizer, in the second screenshot they are enabled. There were no other changes made prior to the shots.