The Pharo is pretty great. Fastest I've ranked up with a weapon.
I also put a stock on my ICR-1 and have been doing better with it. This game is far too spastic to be rooted by slow ADS strafe speed. There must be a reason why I see everyone doing good running like 5 attachments.
Long barrel only increases the minimum damage ranges on SMGs, so it's a sucky attachment for them.
How would you describe your play style? You say that the game is spastic and it seems you're frustrated and having a bad time, while so far I'm having the time of my life. Could you describe, in detail, what is it that is going on?
In regards to weapons, the Kuda is great all around. VMP is like the MP7 from BO2, and relies and sustained fire. The Weevil is the best SMG to use for stealth classes and attacking from odd angles. The Vesper destroys as long as you're able to stay and traverse the map in such a way to always stay in range. The Pharo can kill the fastest of all SMGs (even the Vesper) IF you don't miss. It's a risk and reward weapon. The Razorback is optimal for mid and long range, but like the Weevil, can fit a stealth role. It can survive close range encounters as long as you're prepared.
The KN-44 is the most consistent AR, pretty much always taking four shots to kill. The ICR is the Weevil of ARs. The XR-2 is best for support fire and for attacking while you're behind cover. The Man-O-War is the strongest, but it is cursed with a lot of micro nerfs when it comes to the handling times. The Shieva is an excellent anti infantry weapon, and with High Caliber you only need a single bullet. The M8A7 outguns all assault rifles when it comes to long range, and can easily hold down positions. The HVK-30 is best for mid and semi close range. It's not too shabby at long range either.