SMG are typically used for fast pace, close ranged combat. CQC spec could use them, but everyone else should be trained on the AK-47. Not only is it a durable weapon (I seriously mean durable. You could cover the action with mud and it'd still fire off a whole magazine.), but it also uses 7.62x39mm rounds, which ICly would penetrate much deeper than than the MP5's 9x19 Parabellum (a much smaller, and much less power-packing round), or the MP7's similar round. Granted, the MP7 was designed specifically to be armor piercing, but that's only at close ranges, as well as when firing AP copper plated solid steel, or alloy plated steel jacket. Sometimes they have copper cores, but still, same shit.

We'd need the range with the AK-47s. Everyone does. Not just the Squad Leader. It has the range and the firepower that we need. Realistically, so many AK-47's were produced in such large quantities Roughly 100,000,000 total were made, some copycats, some legitimately Russian made, but regardless, even after the Seven Hour War, there would still be a plentiful supply circulating.

TL;DR-- AK-47's are durable, reliable, and plentiful. The ammunition is powerful and plentiful as well, given the circumstances. It's too good of an option not to distribute among Squaddies. Making it exclusive to leaders is pointless and ridiculous. I'd say give CQC SMGs, and everyone else AK-47's. Give HMGs M249's, and give DMR the SKS. Give the Snipers, so far I know of Janus and Durzo, the M24's, seeing as how if you guys want a legitimate sniper, we need to have a scope.