there is no penalty to sprinting (according to videos thus far). The gun is almost instantly ready to fire again, making ramboing past a corer much less dangerous, as you need less than a fraction of a second to beable to shoot again.
Whereas a longer time to get ready to fire again, might inspire some caution to submachinegunners, without nerfing the guns themselves.
+1
Indeed the recoil of the SMGs seem highly realistic in the game.
The run & gun & circle strafing (even bunny hopping) phenomena is probably a combination of three factors.
1. Staying alive having very little value - will respawn nearby quickly if killed. Desperate high risk, high reward tactics are much more feasable in such circumstances.
2. Physics defying player movement abilities. Can accelerate, switch directions and stance at levels many times greater than any human. Like a mosquito or fly in ways. Erratically moving around. Harder to hit, strike faster. This causes much more confusion, lessening the ability to coordinate successfully in team work. Increases the success rate of the tactics
3. Weapon handling. Switch weapons, shoulder and aim and so on as if having super human dexterity, speed, strength, and as if the weapons are light as paper. This makes it possible to move around so quickly without sacrificing the ability to handle one's weapon accurately and rapidly. Also increases success rate of the tactic.
I suggest reducing the movement, and weapon handling abilities into the real world range. It won't stop the tactic, but it will make it less likely to be so successful while improving gameplay in so many areas.