There are those kind of fans who take it too seriously when their favourite isn't liked equally by someone else. (but their rage is entertaining in a weird kind of way
I really tried to accept the Soul Reavers and the change their presence brought to the franchishe, but in the end, who was I trying to lie, it was pleasant to say hey, I don't like this, that's not Kain's Legacy, instead of keep pretending.
SR1 was really terribly boring with those oversized areas and the enemies you couldn't kill without something pointy edge tool. Both SR games were a carbon copy of Tomb Raider, especially SR2 that cloned the locations and puzzles too. You're right, the whole thing is lacking the wicked atmosphere the Blood Omens had, while BO's characters weren't good or evil but all of them were selfish and cared not with higher causes and other cliches, Kain himself was also a cynicidal sadistic guy, then the Soul Reavers brought the title to the cliche fest of angelic righteous vampires vs the dumbass humas and hylden where the vampires are the competent keepers of the world's balance and of course our new main hero is the victim of circumstances kind of person who keep endlessly pitying himself.
Vampires didn't changed with time, it was just Crystal's excuse to fill the gap between the original Kain character and their own green critter. Greeno not only didn't looked like Kain, it hadn't a single personality or trait that'd had the slightest reminiscence to Kain. Like Conan has not a slight similarity to Yoda.
The other thing about the SR dialogues they were full of pathos and grand stuff like a theatrical play that tries too hard to look epic. I found Kain's black humour and cynicidal comments on everything around him in Blood Omen far more memorable.