I just picked this up yesterday. Got through the training in single player; took the first town without seeing a single bad guy. The second mission, one of two things has happened every time so far: either I stay with my group and almost never see an enemy, or I get too far ahead and get killed. Somewhere there must be a balance; I'm going to play some more tonight.
Still haven't taken it online yet, either...that's something to look forward to for the weekend.