I'm calling total BS on the "vanilla was a one-shot fest". I PvP throughout classic on a lock and a warrior and I was never one, two or even 3 shot. These mythical PvP warriors with their 2500dmg Mortal Strikes or w/e. Remember these videos you saw were a few minutes compilation of hours of footage. It just didn't happen in reality.
Maybe a fresh geared 60 would get one shot - but thats a fresh geared 60 - what do you expect?
Resilience ruined PvP/the whole game for me, since it meant I would have to invest twice as much time to get to the level of useful gear I previously had in classic. So I PvPed much less and focused on PvE.
If resilience was meant to reduce burst...why not just reduce burst? Blizz should work out what fresh 70s,80s,90s will have for HP and work out what it will be at the end of an xpac, then tune burst abilities accordingly. To my mind, it is not at all a problem if a fully epiced max level char can 2 shot a noob green geared character. Don't expect to compete if you have shit gear. Simple really.
If they must keep PvP gear in the game, just make it stamina/crit heavy.