I've played it once so far with the full hero complement (Syndrael+Avric+Leoric+Jain with 'traditional' roles). I am sorry for the rant, but I don't see how it is winnable for heroes if the OL is not doing anything stupid.
Basically, if I were an OL, I would have kept sending goblins for the Caravan site - I get 1 fatigues token even if it gets smashed, and if it survives - 2 more tokens next turn. With their birth rate of 2 and scampering, shouldn't be particularly hard.
Now barghests have +2 health (which is a boon by itself) and an effective movement of 5 (if you account for expand). This is at least as fast as the fastest heroes, without HF/fatigue usage. Now the map is a simply circle, so I can just keep running from heroes, getting at the opposite side of the map. Of course, you could use HF/fatigue and manage to get a strike or two, but I don't see how this kills 4 barghests with +2 HP in 3 turns (because then goblins establish at the Caravan site). And this doesn't take into consideration any OL cards/monster attacks even.
The only sensible thing in I see in this scenario is to get 1 clergy ('cause you gonna loose anyway) and collect all search tokens.
Please tell me I am wrong and this scenario is not heavily OL-favored.