I'll compare to my favorite series, Metal Gear Solid. I'd consider MGS3 an expansion pack. 1, 2, and 4 are all in different generations and each brings something new to the table, so much so that passing them it off order is unsavory. MGS3 is one of the greatest games of all time, but I'd be lying if I said it wasn't an iterative work. Yes they pulled it off, and yes it was worth full price, but if it didn't completely change the way you played, different camera system, camo system, cqc, healing, "open world", I probably wouldn't crown it.
And again, not trying to say Bloodborne is bad, I was planning on getting it for coop till this dumb statement, as I wrongfully assumed they'd be going for a higher frame rate.