I think they're overextending themselves a bit too much. Yeah, you said troops aren't a problem for them, but you also said using way too many troops at the same time would make everyone concentrare their efforts on eliminating them.
Exactly. Now the whole Arkain knows that there is out there a huge army of undead that is growing by the day...
Also btw what happend to Mr. Sarcastic and the 3 Bonelords?
I guess DrakeSkull man escaped, but did the Bonelords' corpses get burned/destroyed?
Knowing Gardon/van Durce they most likely burned the corpses so that they wouldn't be reanimated.
Rahandir most likely escaped. A pity we didn't see Sapphira and Krom confronting him.