Well, snipers do take more skill to be good with, but the risk vs reward factor is completely different between the two. First shotguns require you to throw yourself directly at your opponent. Chances are if you run into more than one person that's paying attention, even if you get a kill, you'll die as well. With snipers on the other hand, you have the range advantage. This game also is extremely forgiving on getting hit while aiming at your target, so even if you have someone unloading a primary at your face, you can land a headshot efficiently. Now it definitely takes more to land a headshot with a sniper than a 1-shot kill with a shotgun, however if you have someone experienced behind a sniper, they have a huge advantage over anyone else. If you go against a sniper pro in trials, good luck actually getting anywhere. I can't say how many times I've encountered teams in trials where there were two really terrible people, and one sniper pro. Well the sniper pro could literally pull away a 10+ kd against any team that isn't proficient with a sniper. There's literally no effective way to counter a good sniper, other than being a good sniper.