I don't mean to light a fire but I have an average connection and I've never once had an issue with getting hit by things. Back in 1.0 I remember getting hit by eruption all the time across the arena so I know it WAS a problem but I haven't seen a single instance of this happen in 2.0. I've even had multiple occasions of reacting late to Titan plumes and barely getting out as it popped and not taking damage.

Also, skill activation is more based on animation than global cooldown. Some skills won't go off if you started a longer animation skill prior. Hallowed Ground however is a pain in the arse.