I'm not about to quantify anything. I suppose I've seen too many raid bosses but for me it's mostly just a different dance to learn. Some are fun, some are not. Sometimes the dance has something to do with progressing a storyline but often not.
I did like SoO as a 'story raid' because gradually working your way up to and through Orgrimmar was pretty neat all told. But the bosses themselves? I dunno. Again, just a different dance to learn for each one.