I've always thought that the most conservative team would always win in any team game. Laying back and covering flanks. Even the most coordinated team of scrubs can outwit a team of good players if they stay back.
I was playing ragnarock and noticed that there a good number of decent enemy players helping keep our team from pushing past 1/3rd of the way and forcing us to take cover, yet we still won.
I was thinking that FPS's are self balancing as far as team psychology goes. A team that has a bunch of good players will try to outkill other good players and will be more willing to put themselves in harms way, while more conservative players will stay back minding their KD ratio and have the rest of the team "ruin the game" by sucking hard trying to rush and dying to get kills.
So do you think a team of scrubs acting defensively will put up a good fight against better players?
Put up a good fight? Yes. Win? probably not most of the time.
If you are a team of scrubs hanging back and taking cover a lot, its a good tactic but, eventually the better team will close the distance. From my experience the better player will win in a close range fight. Once they start picking off the scrubs and the "bad" team starts respawning in random spots on the map it will be over for them.
But I don't think you need to be the BEST team to win consistently. You just need to actually play with people that communicate. You know, call out what the enemy is doing/driving, sniper locations, people with power weapons, vehicle spawns and attempt to come up with some strategies if things start to go downhill.
Most people play the random matchmaking without a headset so those teams might have one or two really good players that present a challenge. It won't make up for all the other people not minding their K/D running into the open and getting killed by a well organized team of mildly skilled players.