Squad and Squad 44 come with plenty of team mechanics, and I have never joined a clan before. It does depend on the server, and also on who steps up to be squad lead. But generally I find the team mechanics to be fairly deep. If your team is not working together (strong squad leads, medics, logistics, etc) then your team falls apart and you will lose (unless the other team is just as bad). Logi in particular make or break a match a lot of times.

Saw that at its peak recently when Galactic Contention (star wars overhaul mod for Squad) came back online. Bunch of new casual players who didnt know how to play building emplacements but no ammo boxes, no one building or supplying FOBs, no one running medic, and we got our asses beat.