ok here is what i put together for each game type, here are my team strategies
S&D: one person needs to have extreme condition and juger. one sniper needs to cover the the runner, which means sniper will need to have extrm. condition on as-well. 2 people will need to have either silenced assault or smgs or red dot lmg's for covering/suppressing fire
DOM: self explanatory but C4 needs to be tactically inserted so enemies can't take over flags, also with teams of 4, 2 people need to capture flags and 2 snipers are need to cover open areas
CTF: sort of similar to S&D, you need the same strategy but the sniper needs to hang back and cover the flag and flag runner, preferable there needs to be two snipers, one runner, and one lmg/assualt
HQ: simple, get 2 guys in to capture and 2 guys to hand back and defend...snipers are not needed here but can be useful on large maps, but small to medium, snipers are not needed.
SAB: ok this game type is a full team effort 1 sniper, 1 lmg, 1 smg, and 1 assault with under-barrel grenade launcher. you have to be a pack of wolves here, sniper hardly ever goes rogue he is the top cover, the other 3 cover while a runner retrieves bomb, runner then joins pack and you run/walk bomb to objective. Once at objective runner plants bomb with no one in the flash/stun bang radius. sniper is on point looking towards the bomb sight and not away from, the lmg and assault need to find ambush and choke points to hold runner needs to cover the objective