Lets put the whole Jackal mess aside for now (it's a minor imbalance that can be easily fixed) and look at something that Crytek genuinely intended to be part of the game that wasn't a part of Crysis 2 - OHK weapons.
I'm referring to:
> Bolt Sniper
> Xpac Mortar
> Swarmer
> Gauss
> Bow
There may be one or two that I have missed, I don't know whether the automatic alien rifles (Pinch and Reaper) are insta-kill on non-armor.
The first 3 weapons on that list will kill you instantly with a direct impact regardless of whether you have Armor on or not. You don't have a say in whether you live or die, your fate was decided when your enemy pointed his cursor in your general direction and clicked.
The last 2 weapons on that list will instantly kill you if you don't have Armor activated, or don't have Auto Armor.
At this point a lot of the "top tier" players have dropped Auto-Armor because they know the maps and movement well enough to not die to newbie-average users of Bow/Gauss. But please tell me, what happens when that Bow/Gauss user knows what they're doing and can almost always land their first shot on you from across the map? Do you feel you were killed fairly?
How about when you are destroyed by an alien weapon, do you feel you were killed fairly, that you died due to your mistake, or your opponent's amazing skill?
In general, how do you feel when you are OHK'd by a highly powerful weapon?
Since everyone has access to said weapons, one could say all is fair in love and war - but on the other hand, one could also call it a 1-shot-kill mess.
Do you feel it suits Crysis 3's fast-paced gameplay, or do you feel it is a step backwards from Crysis 2's more "disciplined" shooting where your skill mattered more than the jizz-cannon you were holding?
This also applies to players who are heavily into Cell vs Rebel, I know for sure that Gauss/Bow are always OHK in that mode no mattter where you get hit.
Remember this isn't a minor balance concern, this is a laundry list of weapons/mechanics that were intended by Crytek to be that way - so lets keep the discussion about the weapons I listed above i.e. alien weapons, swarmer, gauss and bow.