You forgot about 1 thing - recoil. If scope is added, recoil can be increased. For example, leave current recoil while shooting with laser sight and increase it by 50% while using a scope. Wtf, tier 3 commando weapon has a scope, but same tier weapon for sharpshooter - hasn't!
Yes, with M14 can fast clear room from trash... but commando with SCAR does it better.
Yes, with M14 can kill FP... but demolitions handle this job better.
So if you are playing solo or in a small team, then M14 can be useful. If you are playing in full team (5-6 players), then take a xbow, or choose a different perk.
Now lets talk about laser sight of M14. When pointing though the smoke, you should be able to see the red line in it (in real life you can check this by turning on laser pen in the fog). In the game you see nothing: no line and no dot. So if there is demo in the team, forgot about using M14.
On some maps with reddish textures (wyre outside, hostital roof etc) it is very hard to see the red dot. And if other player is using M14 too, it's a nightmare, cause you get confused, which dot belong to you. So I suggest to implement different colors of laser sight, i.e., pressing alternate fire button will cycle laser sight color between red/green/blue. Also laser sight color and state (on/off) should be remembered when next time switching the weapon.