By the way, my current fort has faced an invasion force of 14 goblins without much trouble. Do they get bigger or badder than that? I hope so cause I'd like to see how they handle something more in the neighbor hood of twice that.
Later on in the vanilla game, I generally get sieges of 4 or 5 squads. At 16 per squad, that's 64 to 80 goblins. I usually manage to cage about a fifth of them, so right now I have a dungeon with about 240 goblins, color-coordinated (rows of wrestlers, archers, etc). It would be rather funny if I installed a new version where, unbeknownst to me, goblins were suddenly able to break out of terrariums and free each other - the single watchdog might be overwhelmed.
I think that if you want a challenge, simply playing without traps would be sufficient, if you start in a location where the goblins are at least hostile. Starting near hippos is a good idea, too. But if you want to have FUN, then use a challenge mod.
It's unfortunate that there are no good farming mods out there right now (IMO). The ones I've read about do not address what I see are the major problems, namely, that you can support a huge fortress with a single cook, a brewer or two, a handful of farmers, and an 8x8 square of land - and still buy out every caravan with a couple plates of leftovers.