For me it's more about the dynamic. Dom!Harry to sub!Snape is not the same as just who is doing the fucking, at least for me.
RE: comments-it seems like people were posting yesterday but not necessarily reading. Although, I have to say, I had to bypass yours since it's the longest HP fic on the list. I have every intention of reading it tonight or tomorrow. I think long ones like that do get put in the "to be read" file sometimes.