The dynamic spawning seems to be really screwy if not outright designed to piss people the hell off.
In a cave by your self surrounded by mobs? Mobs will spawn right behind you every 3 seconds.
Outside with 10 other people trying to collect bandit nipples for that goblin fetish quest? The next mob will spawn in approximately 7-10 business days.
STV is a PvP area. It’s a farce on PvE servers for the reasons you’re complaining about. It’s actually the best zone in the game, but you have to play without training wheels.
Honestly? Group up if it is a kill quest. Level elsewhere if you’re looking to grind, at least until people push through the STV level bracket. Mid-30s to mid-40s is a kind of bottleneck area. Only a couple zones work for it, and STV is the easiest for everyone to get to.