Then what's the point of overcharged mode?
Instant death as in no armor or invuln save? No thanks.
But that's only when you intentionally take an overload shot and roll a 1. If you use it's 'normal' profile of Strength 7, D1 (not sure about AP), you're not in any danger at all. This is a huge improvement, in my opinion.
The point of overcharged mode is to make it easier To Wound, and to do more guaranteed Damage. Since the S vs T has changed, a Strength 7 weapon, like the Plasma gun, will no longer wound Marines on a 2+. It'll take a 3+ now. So, in a typical scenario, your Grey Hunters are going to want to use the safe 'standard' firing mode for their Plasma, although it is a little less deadly than it was in 7e.
However, if a unit of enemy Assault Terminators teleports down in front of your Grey Hunters, but doesn't make it's 9" charge range this turn, in your Shooting phase, those Grey Hunters armed with Plasma weapons (2x Plasma Guns, Combi-Plasma on the Wolf Guard Leader, and Plasma Pistol on a Grey Hunter) are all probably going to want to take a small risk and shoot in 'overcharged' mode to ensure they kill as many of those enemy Terminators that are about to demolish them in the next enemy turn. They'll die if any of them roll a 1 on their To Hit roll, but they were about to die anyway. And this way, any that don't miss have good odds on killing a 2 Wound enemy Terminator outright.
If it's just take a wound then it's not so bad but if a deathwing terminator is just upped and removed because he rolled badly with his plasma cannon I'm gonna call bs.
Obviously we haven't seen the actual rule so this is all conjecture, but I'm not very sure about this.
That Deathwing Terminator
would only take 1 mortal Wound, so he'd have another Wound leftover, but it would only be a risk, again, if he chose to fire in overload mode. EDIT: corrected to say, yes, I suppose he'd be killed outright, since that's what the rumor originally said (I misremembered and started thinking mortal wound), but it is easily avoided by not trying overcharged shots unless under extreme circumstances, such as just above.
Edited by Valerian, 26 May 2017 - 04:18 PM.