for me, woltk was near perfection pvp wise. the pvp was just so good, i still to this day dab into private servers and play competitively. Aside from some slight class balances. Most classes could be played at a low skill level and be fun while still being extremely strong if you were excellence. better talent trees(imo) hybrid specs made for some fun battleground troll specs. Burst was there like it is now but to me it still feels more balanced and tactical. CC chains were less polished but still had its own flair.
It was also the last expansion where you could near 2 shot shit with a 2h'ed enhance but that besides the point.
PVE also blew me away but i did it casually.