I vote for the 4 layer approach: Cooper, Platoon Leader, Squad Leader, Cannon Fodder.
I'll mostly be playing Cannon Fodder but I have invested in a spawn beacon if I'm designated squad leader for some absurd reason.

I'm an advocate for the Platoon Leader to only give general squad instructions: go take that and leave the rest to the squad.
I'm not so sure that being proactive on defense is that fun an idea though as there is a fair chance of a squad waiting in vain for a while at a desolate outpost in the middle of nowhere.