As i have red more then once : being realistic or not isnt a good consideration (as if the rocket launcher is realistic modeled) for making decisions. You have to question the gameplay aspects and the gamers mental image of the gameworld. Of course the latter can be often taken for realism and that is where the mistakes can slip in. Keep this in mind please before you interpret other messages and blast at it, for the poster might have meant a different idea and you might have understood another idea. Take a step back before reacting, in particular for non native english speakers ...
Winter knows full and well what he's saying and what I intended to communicate, given that he's a brit, however, the point is taken all the same. While I agree that realism should almost never be a primary consideration (gameplay is most important) the fact remains that a lack thereof is definitely a negative, at least in so far as UFO:AI is concerned. Because this is so, it is important to demonstrate that the feature is reasonably consistant with reality and logic.
Coup de grace again
Not for melee weapons?? Surrealistic, why? The main purpose i can see is for melee, for it is the place where stealth and being unspotted can be translated to a chance on higher damage from an attack (eg slit throat vs a quick jab if spotted).
For fireweapons, the damage multiplier should be much lower. An unaware enemy is more predictable thus you can in the same amount of TU's have a better aim at his weak spots, but the advantage you have here isnt up to par with the melee advantage.
I never said that the feature wouldn't work with melee weapons. You may have misinterpreted the statement that the feature was not meant to
encourage their use. Also, melee weapons should benefit from the coup-de-grace no more than ranged weapons. The reason is because the difference an attack on an oblivious target makes in each case is uniform. With the gun, you get a free hit on your target's vitals. It is no different with a melee weapon. We are talking about pointblank range here, while your opponent is unaware. It's not that your opponent is merely more predictable, so much as that his weak spots are nigh unmissable.
As mentioned: in the absence of a body part system (distinction headshot, legshot), the criticals does fulfill that role partly. That being said: a body part system would be cooler.
Just like there is weapon variance, the critical system can be tweaked to keep the odd on a short leash. Thus as Surrealistic mentioned, if we tweak it, you dont have to fear that chance will run ramparant in the combat. But i still am not sure about the control you have over it, which is also to consider for it being random or not. The mechanics you suggest (weapon choice etc) are but second order effects for they serve to control very other tactical decisions and not to control the critical hits. I am looking for decisions you have to make that ONLY (or nearly only) affect criticals and nothing else.
The 100% chance for snipers makes me frown. For a x3 damage for critical hits and a 100% on criticals is the same as a no critical hit system with the base damage x3.
A number of things. First of all, the near 100% base critical rate for the sniper rifle is specific only to the Headshot fire mode. Secondly, that probability is further modified by other dynamic factors, such as the type of alien, and the shooter's skills, so the effective average damage output overtime cannot be accurately modelled with a mere increase to the base damage. Thirdly, critical damage is 2x, not 3x.
That said, there is no realistic way to increase critical rates without signifigantly affecting other considerations. There is a necessary correlation, between slower, more TU inefficient aimed attacks, and increased critical probability. You cannot divorce one from the other, save with exceptions such as the coup-de-grace.
While I would love a body part specific aiming system ala Fallout, this would demand considerable effort to impliment, requiring a new interface and differing part descriptions and properties from species to species as the alien physiologies vary widely from one another, especially when it comes to the non-bipedal/humanoid and mechanical instances. This is probably not worth the work it'd require, when a critical hit system by comparison is simplistic to impliment, and abstracts hits to vitals with reasonable accuracy.