Malefiz said:
If you do further calculations for other Heavy Weapons (and believe me when I tell you that it doesn't play any considerable role for your flashlights... your bought SS for your Heavy Weapons anyway, right?), you will find out that Sharpshooters actually leads to the largest effect with lascannons or other single-shot weapons such as Missile Launchers, and even then it's barely significant. What's even worse, the increased kill potential you create with SS is usually as, if not even more, expensive than simply using another squad with the same weapons and without SS instead (with the added benefit of more warm bodies attached to those weapons!)
Not true.
In terms of dealing damage, SS and non-SS squads are exactly identical in terms of points paid per lasgun hit generated. Spending the points on additional non-SS squads, however, is advantageous because they provide additional wounds and can hold table quarters.
But, when it comes to special and heavy weapons, the increased kill potential is *always* less expensive with SS squads than it is with non-SS squads. This is because the cost of SS is based on basic, lasgun-toting guardsmen. If they have better weapons, those weapons are improved for 1 point per model, same as for lasgunners. Behold:
6 SS Squads with a grenade launcher and autocannon in each [558 points]
35 lasgun hits; 3.5 grenade hits; 7 autocannon hits
7 Non-SS Squads with a grenade launcher and autocannon in each [581 points]
35 lasgun hits; 3.5 grenade hits; 7 autocannon hits
SS saves you points. Right here, you save 23 points. Is that insignificant? The more expensive the heavies and specials you equip, the more points you save. I agree with you that extra bodies are generally more important than more accurate troops, but the arguments that the advantage of SS is "insignificant" and that SS troops costs more per hit just are not sound.
EDIT: The Marine example is also not a very good demonstration because you use all the math simply to say 1.9% is a small number. The math should look more like this:
SS Lasgun firing at a Marine:
7/12 to hit * 1/3 to wound * 1/3 to fail the save = 6.5% chance to kill a Marine
Non-SS Lasgun firing at a Marine:
1/2 to hit * 1/3 to wound * 1/3 to fail the save = 5.6% chance to kill a Marine
All right. Now we've got a 0.9% difference between them. But this is not a tiny insignificant percentage. This means that, relative to each other, sharpshooters are 16% more effective at killing Marines than non-sharpshooters. That's hardly insignificant.
Another issue is concentration of fire. Sharpshooters, by nature, will make each unit hit harder. Extra units are good for holding quarters and soaking fire, but the idea that they will generate hits is giving them the benefit of the doubt. They could just as well be out of LoS. Just because you *can* buy an extra squad with the points saved on sharpshooters, doesn't mean that that extra squad will be in the right place at the right time. In a one-off basis, the sharpshooters will outperform the non-SSers.