Yeah, screenshake is ridiculous. Sure, if a tank blows up near me, or someone unleashes a high damaging/explosive/concussive blast near me I get it. Those kinds of scenarios make sense. What doesn't make sense, is a tank blowing up across the map, and shaking the screen. Or an Eldar shooting a Tempest Launcher across the map, or completely on the other side of a building, and the screen shaking. Or anything really where a screenshake causing action happens either too far away, or on the other side of a solid barrier that should protect you. It's more annoying than all hell when you get the drop on someone, line up your shot while they are unaware, then the second you start firing something happens halfway across the map that causes your screen to shake and force your aim off. Which then causes you to spray 10 shots past your enemy's head, and they turn around and engage you. Fix the mechanics of screeenshake, make it more bearable. Especially the "halfway across the map" shaking, and weapons like the Tempest Launcher that can create screenshake when not even near the blast radius.
Two ranged dudes are scrapping it out, one has the effects on and the other doesn't, insert explosion, take a guess who wins... this doesn't really seem like a reasonable option. Shouldn't have to turn it off it you like the effects just to compete.