Vashj was only killed twice in her original form. I’m not 100% but I had always thought that Method and Nihilum were the ONLY guilds that killed her while persuasion was in the encounter, and the Nihilum kill was the bugged kill (and even they admitted it shouldn’t be considered a legit kill). If that is the case then that means only 1 guild got 1 legit kill on the version of Vashj we have on Classic atm, up until now. So this version of Vashj is basically a buffed version compared to what even the earliest kills back then had to deal with (save 1-2 guilds w/ 1 ‘kill’ each). This is not the content you or most anyone else (‘hardcore’ included) remember from back in the day. At least for Vashj 
There were also myriad other bugs in the encounter that made it more difficult (as these VERY few guilds to reach the content that early back then were basically beta-testing, as there was no PTR back then).
Btw, this doesn’t mean I’m for the nerfs. I think they should give the original, hardest forms of the bosses (as long as they’re killable) and never nerf them at all. Ever.