Pretty sure it's typical RPG logic. The 50 or so drunk goblins at the ruins are just there for flavor. Same with the 10 goblins that show up to attack the grove. This isn't exactly Heroes 3 or Mount and Blade so you don't have the option of upgrading your castle and training an army to fight off the entire horde of 1000 goblins. WoTR tried to add that with the overland crusader map and most people didn't care for it (and I can't blame them). I guess it's generally accepted that in RPGs the focus is on individual characters and their stories and everything else like goblin hordes, huge cities, and massive armies is abstracted. There are other video game genres that focus on those things instead of character development but you can't have everything.
