Weapons mechanics are out of whack (so to speak). There is an-unrealistic approach to caliber and damage/recoil. 7.62x51 should be more effective in semi-auto with a double tap mechanic. 7.62x39 should not be as controllable in full auto as it is. 5.56x45 should be quick rapid fire, but still be affected by recoil on full-auto. Bring back the old mechanics of the first insurgency, at least try to replicate them in this new engine. There is an intensity/immersion factor that is severely lacking from the first. I fear that the developeras are catering to the new players (CoD/battlefield fanboys) for more profits. Put simply... Why fix something that wasn't broken. Get back to old insurgency mechanics and keep the intensity/realism.
Caliber mechanics are more realistic if anything. 7.62 x 51 and x 39 are not effective at penetrating armor plating. They however, penetrate materials far better. 5.56 and 5.45 penetrate armor well but not less dense materials. The mechanic isn't perfect, but its waaaaay better than ins2.