Bear in mind, that score we did against Kunzite was not typical and should not be treated as such.
We found a treasure chest -- only one of several cards in the deck -- and got lucky with dice rolling in the secret passage and Shop Item Deck draw from there. On top of that, some lucky dice rolling for the Unknown Treasures rumor helped us make an educated guess on the remaining face down cards, and we walked away with a discounted Dragontooth Hammer and a regular price Tival Crystal. There was no actual skill involved, just a lot of dumb luck that left us with a payoff we probably couldn't replicate if we tried.
Getting back on track, I suppose swarming harpies and kobolds wouldn't take much actual "skill" either; Mob the hero who is the biggest threat -- even easier due to Fly and the boss Harpy's Flock skill -- and swing. One surge gives a maximum bonus of +8 damage, for ONE attack. Repeat with each adjacent monster until the hero dies. It's not guaranteed, but it only has to trigger twice out of many separate attacks (not counting OL cards) to deal lethal damage to most heroes. While I suppose it's counter-balanced by the fact that the monsters are now bunched up, a dead hero is a dead hero; one that can't effectively stand up until the pack is thinned anyway.
The only way around that is to kill an appreciable number of them before they have a chance to get that swarm effect going, but any OL worth their salt -- Like our crafty Kunzite -- isn't going to start with all her monsters bunched up if the heroes have Blast or have ways of attacking multiple times a turn.
+1 except I believe the most bonus is +7 since swarm says "each other adjacent monster" to the hero. Nine squares in a box, hero in the middle, and the attacker = +7 if totally surrounded.
The Basic II card Overwhelm makes me laugh at all this!
Putting all your monsters in one place is high risk, high reward. Bread is correct. Leaving all your monsters in a nice package for the heroes is dangerous, but if the hero falls and the OL gets a reward beyond one OL card (Bloodlust is my buddy) this it's VERY worth it.
Also, that pesky rule that all of one monster group has to be activated before another group can mean that one group is stuck in harms way before the OL can move them. That means all of that group can be lost. The Kobolds aren't an issue. There are NINE to start off with. 12 can be on the map at once if the heroes are smarties and kill the three masters first. I would be concerned about the harpies making it out alive after the assault. But if your goal is to take down hero problem number one, then you got yourself a good piece to work with. If the hero that is taken down is blocked off by the group also means trouble. The group will have to waste actions to free their fallen friend or forfeit bringing them back. This has happened.
As for the treasure room being an isolated incident, it is true. My heroes have been drawing the search cards pretty well, and picking when to go into a treasure room very carefully. I fight no fools for heroes.
BUT! I would like to know what others think of the new OL class, injector! It looks interesting... Another dark charm but better as a level three. <3 I like it! It seems VERY powerful. Land a hit on a buddy (or have them hit themselves) and then separate them from the group seems really dirty! Also, there are cards that sit out for the whole quest. Thinning out the deck while keeping the pressure on the heroes seems really good. <3