When you play a deck full of bombs, you get broken effects.
When you play a deck with incredible synergy, you also get broken effects.
Fish can get away with budget brokenness because the entire deck feeds off itself. Every card in it has two uses, and from this incredible utility comes power. People tell me that Fish has a slow clock. When it gets going, Fish sets its own clock. With enough denial, you can swing with Conclave for the win. Any faster clock (Jackal Pup, maybe) slows the deck down because it is one-sided.
Fish is the anti-power deck. Think back to Trix extended, where you had Trix and Anti-Trix decks. Fish is the Anti-trix, but it screws every Tier 1 deck instead of just being hate for one. It has successful counters to any big plays (Wasteland, Stifle and Null Rod do most of the work).
I always hear people say that Fish is a metagame deck. In the past, yes. I disagree now. Fish can survive in just about any metagame, thanks to recent sideboard additions of Sword of Fire and Ice and Sigil of Sleep, both serving to shore up the weak dedicated aggro matchup.
I simply couldn't agree more.
I have been on a six month haitus from Magic - it's given me a long time to think about game theory and the deck I love. I am confident to this day that the "gay / fish" archetype can survive in any metagame given a decent player to back it and sufficient metagame analysis / knowledge.
If you go to a tourney with a sideboard tweaked for a general metagame - I would think you would do fairly well. If you did the right thing and scouted the area before the tourney ... I'd say your odds would increase.
The reason I've always preferred those lousy 1/1s to Mana Drain is simple - I consider 1/1s to be far more of a threat than Mana Drain. Mana Drain isn't a threat ... per se - it's an answer. If you're lucky, you can garner a threat out of the result of the counter. I recall conversing with Phantom Tape Worm about how good of a deck Landstill is, but I feel the threat density of Fish is why I will stick with it. Sometimes, believe it or not folks, you simply crap out too many dorks for them to handle, and win.
It is the versity of threats, the access to heavy card draw, and the fair amount of permission that binds the deck together and makes it successful.