[llamabeast]

LA C'tis is a bit different. Sure it would be annoying trying to crush a fortress containing an endless supply of longdead. But eventually you'd just get better research and bring along an SC or group of mages that could kill unlimited undead. Massed longdead are only a problem in the early and mid games, so eventually the player who has provinces will win. Also there is no versatility - you cannot turn longdead into more mages or anything like that.

Massed clams, however, only become more valuable as the game moves into late game, and you can use the pearls to get more wish casters and make more clams and so on - there's no limit to how powerful you can get, trapped in your little fort.