There's some things in there I agree with but a lot I don't agree with too...Particularly your 'styles' thing, remember NPC's can do anything you can do, and generally, they're better at making sure they hit you with it too. I'm pretty sure no instant kills will ever make it into player skills even if they have to be low HP first, and I'm almost as sure no such thing would ever enter a NPC's ability range because that would only cause frustrating and 'unjust' deaths that mostly only happen by chance. There's no real way to know what % of HP your enemy has left or something like that, you can take a guess by judging the bar but that's as far as you could get, the NPC however would always be able to recognize your exact values and use the appropriate attacks and always get the effects they wanted. Bad idea. It feels like you were trying to make up for the weakness of melee weapons by giving them powerful 'specials' that's probably not the best way to go. Oh and explosives are a nono. Consider enchanted grenades. Free AoE magic effects? Too much? Definitely.
I like how you brought up chance there. Did you read part III? Learning to dodge can avert a lot of death if you can do that. Also, there was a section with 'Contests' that could occur in melee as well. In that example, I was actually using getting disarmed as an example of something a contest would be held over, but something similar could theoretically be applied to a slaying attack.
Besides, such instant-death attacks would probably be applied to only high-level attackers; 50 skill in a weapon or higher. And of course, there are plenty of other choices in attacks that can be put in the various slots for charge attacks that aren't instant-kill. See, in your example, you're assuming the absolute worst; an NPC that uses every single technique correctly against the player with optimal setup. If Bethesda had any common sense, they'd probably have AI that's somewhat weak, doesn't use everything quite correctly, and probably doesn't even have an optimal moveset set up as part of their attack skills.
As with health percentages and that discrepancy, It's a bit interesting to see; Health values in patched Morrowind were extremely easy to calculate, since they were on a straight, clean-cut yellow bar. You could easily tell when your opponent was at 50 or 25% health, but not necessarily how much health they had in concrete numbers. On the other hand, the enemy health bar in Oblivion... Seemed sort of random. There were times that the enemy could appear to have a sliver of health left, and yet would still take 15 hits to kill, when it might've only taken 3 hits to bring him down to that level in the first place. Thus, I can see how you could say there's not any way to know % of HP left on the enemy... Unless the enemy health bar had increased accuracy like that of classic Morrowind. Simple as that.
'NPC's, however would always be able to recognize your exact values and use the appropriate attacks...'
That sort of AI would probably only be reserved for, like, master fighters; marauder captains, arena champions, and cult leaders. For most grunts, I bring up the 'weak AI' thing from three or so paragraphs up; a simple, half-baked warrior would probably have only learned the moves, but didn't exactly know when to do them properly. Thus, they are fail fodder for most but the least experienced of adventurers.
As for grenades, I had previously mentioned that they are hellishly expensive; to get a single grenade with an enchantment stacked upon it would be freaking awesome, yes; you could cause like 800 damage or something with one, but consider this; if grenades were implemented. I don't think all but the stupidest of creatures would say 'Oh, it's a grenade. I think I'll just stand here and take it in the face.' No, they'd run like heck. And of course, if they're trapped... Well, svcks to be them. But anyway, there is nothing 'free' about those AoE effects; a single damn grenade would cost like 1000 Gold for something of middle-caliber; getting a single use, 200 damage, 30 yard bomb for 750 GP would easily be a bargain. Even then, because of how most enemies would react to a grenade, it probably wouldn't be overpowered at all; the weapon would easily prove most useful against things like zombies, rats, goblins (maybe?)... ETC. And walls. Easily, the best usage for an explosive weapon would probably be in a 'mine' dungeon, where there are caved-in stone blockages that can only be easily cleared with a bomb.
» Wed Sep 01, 2010 10:34 am 
Though for future reference, it's generally considered acceptable to snip quotes if they're of significant length by highlighting everything inside the qoute tags and replacing them with "snip". Provides less quoted material for us to scroll through whilst still giving us a link to the original source. 
We're lazy like that.
