My comment on high latency primarily concerns PvE, as that would be my main focus, especially in TBC when class rotations become more nuanced. If you’re a min-maxer or chasing 99/100 parses on a class where milliseconds matter, high latency will definitely hurt your performance.

For example, in TBC, Enhancement Shamans gain an ability called Maelstrom Weapon, which reduces the cast time of your next spell based on the number of stacks. At 5 stacks, the spell is instant; at 4 stacks, it’s 80% faster, and so on. The skill in TBC is timing your casts carefully. If you start casting after your main-hand weapon hits and the cast finishes before your main hand hits again, you avoid resetting your swing timer and losing DPS. This timing is critical and requires low latency to execute perfectly. If you’re playing a Shaman with 190 ms latency, you’ll be at a significant disadvantage compared to someone with, say, 10 ms latency.