It is incredibly stupid that an autocannon round can do all that damage to a person but not kill them, only for a punch to that person's thigh next round causing his leg to become a hand-grenade, though.
That's very similar to someone with high Wounds losing a whole bunch to a heavy weapon and feeling no ill-effects, and then suddenly someone punches them and they start going to pieces aka DH1. At least in the DH2 version, there are likely effects before that incrementally building. Also you can feed into things narratively with very little effort. In the example we're talking about the character is dazed and stunned and if someone walks up to them whilst they're still swaying and grabs them by the neck and slams them into a wall - yeah, they get their skull cracked and they die. That is pretty much what we're talking about - an autocannon hit and then an unarmed physical. But it sounds alright, doesn't it? Even the specific example you gave - a leg hit, I can make that work pretty easily. You spot a piece of sharp shell casing from the autocannon embedded in their thigh. Grabbing it you push it in further / yank it downwards slicing open their leg. As the arteries spill out, you produce the "shower of blood and gore" described in the Impact Limb result.
There's a basic choice here - FFG produce the world's largest role-playing book, or GMs exercise a very small amount of descriptive freedom adjusting the wound effects occasionally as needed. It even prompts you to do this in some places, though really, if you shoot someone from behind and the result says it hits you in the forehead, then I do not believe that any GM here should have a problem altering that flavour text in a tiny way as needed. So I don't see big problems doing so anywhere else. And I want to keep the existing wound descriptions because they are useful to me in a way that a bland mechanical listing would not be.
Yes, well put knasserll. We've all been playing with a system (1e) that was pretty terrible at this. DH 1e combat had you behaving in tip-top physical condition even though you were heavily wounded and wearing 70lbs of gear. Then you went from diving, rolling & sword fighting with zero ramifications - to dead from a moderate amount of damage.
This is a great opportunity to keep crunching to get 2e as right as possible, but it's still useful to assert at this point that, in this particular aspect, there's a good case that 2e is already better than 1e (we just got used to it in 1e). Still needs work but it's better than what we've all already have been using.
Another good point you make, is it's perfectly realistic and reasonable for a character to take a blast, be near death & to be finished off by a moderate amount more damage. That's realistic, not un realistic. A lot has been made about this in this thread and on this forum - but I don't think it's something we should be trying to fix.
If anything, it's simply the Wound descriptions that are in question for this. I'm okay with discussing how to make the Wound Effect tables more accurate, but everyone has to admit that to try to have them describe every possible situation accurately is a very tall task.
I actually find more compelling the question of whether +5 for every previous Wound suffered of any size is the best number to use. There's a case to be made that it makes the lasting effects of small wounds too big and big wounds too small. I'm still captured by the notion of making the cumulative Wound Modifier the amount of damage actually taken: +1 future Wound Effect Table modifier for 1 point of damage taken and +15 future Wound Effect Table modifier for 15 points of damage taken. This way would perfectly represent the size of the wound.
It's worth noting that this is the way that 1e handled multiple Critical Wound effects and I thought it worked quite well. In 1e, if a character suffered damage resulting in a "2" on a Critical Wound table, they suffered that result on the table and the next wound suffered would get a +2 to the next damage result on the Critical Wound table. The +2 exactly represented the "2" they had before on the table. Simple & perfectly representing where on the table they were before.
I'd emailed Tim about something similar to this (give the glancing wounds only a +1 to later wounds rather than +5. His main issue with that was how much it would impact the speed of combat. As it is now, if you're damaged 6 times you're either incapacitated or dead. That is anywhere from 1-6 rounds (more if shots miss) in single combat. That's already a pretty long combat. The +5 is putting a firmer cap on combat length, though, which is appreciated.
Maybe it would help to run some simulations on combat length using these differing rules. Another awesome poster whose name escapes me has put up 3 excellently written combat simulations. Maybe we could try rewriting them using some of these alternative suggestions?