This is what gives AoS that edge, the bullet count, yes I would like some bullet drops but this would need to vary A LOT as I wouldn't want many bullets, as managing your ammo is a key aspect to this game as well. SMG indeed has a lot of potential, it can take out Rifles too, if it had more ammo, in my opinion; it would the most used weapon, as it is easy to mis-manage your ammo and run out of clips for SMG.
Secondly, coming to a serious debate about nerfing headshots - Just go use some bloody cover, in real life (Yes this is a game, but it has some aspects of real life like headshots), if you get your brains blown out by a shot to the head, you die, you don't wait for fucking 5 shots to the head (20% damage per shot) to die, use some godamn sense.
You know it is very, very easy to die from a headshot when staring down your sight as it slows you down and blocks some view from sides? Thats why you toggle it on and off, so you can see where people are, so you can avoid having your brains being blown out. I don't know what game you play if you think Shotgun is useless, because a lot of people moan about its power in close-midish range, and for SMG, you must have your eyes closed, because I've seen people use it as a Sniper except with more bullets being used, hitting right for the head, despite the range or recoil.
I don't even know what the hell I'm reading about sneaking, but crouching does the job fine, this isn't bloody Splinter Cell with Sam Fisher, this is a game based on WW2, not a 21st Century technology advanced warfare based game, where you can go wherever the sodding hell you want without spilling some enemy blood to avoid being killed.
If you die, it's your own fault, I've seen people stay alive in the battlefield for a decent amount of time without dying, because they don't jump the gun and rambo in like Leroy Jenkins.