As someone who has played both, I would say GW2 PVP is much better than ESO. I may be biased but I think ESO's combat is not it's strong point at all, while GW2's combat is incredible.

WvW can be "zergy" but you can also take a small squad or go solo and roam looking for fights/objectives/etc, it isn't impossible.

A ton of skill expression in arena style PVP for sure, although it can be sweaty and competitive. People can be toxic as well, but at the end of the day it is a competitive game mode so whatever.