Maritime is BEGGING to get slapped with a nerf stick. Of the city states, it is the ONLY one that scales VERY well with empire size, militaristic and cultural both give less relative returns for larger empires.
In a balanced game maritime will not last long. The food resource tiles themselves are fine and make the total tile yield stronger than others. Terrain does actually matter in this game.
But nerfed how? Currently I like the idea but I think it's FAR too easy to get. For 500g you could buy a... library? Or +2/1f in all of your cities?

I too feel that the lack of tile diversity is THE main reason the game is a step backwards from Civ4. Never before in a civ game was terrain this garbage. Trading posts literally everywhere is the only rational way to play this game. Even Civ3 had more diversity. Land=power like never before when it hardly matters what terrain you settle anyway. Cities are good only because you can mass them, it would be pointless to grow less cities to work more garbage tiles. Buildings take an era to build no matter how large your city is (seriously who at firaxis thought it would be fun to completely screw production?) so that killed the game for people who enjoy a quiet builders game. The AI is beyond psycho.... you can't trade techs, maps.. Even CivIII had more depth and logic to the diplomacy system. Firaxis has literally stripped us so many facets of previous Civs that we are left with a game that must be about war, every game.
It is fun only because Civilization is a fun concept and it is new (which is why it will continue to sell well and get good ratings). But I can't believe that anyone who seriously cares about Civilization (Sid???) would think this is a worthy successor to 4. It is a step back on so many levels.
I have no doubt in my mind that I will get bored of this game in the next couple months, and I will return to 4 until some expansion or something reels me back in and it's new once more. You've got me, Firaxis. But I'm very disappointed in you.
EDIT-And I HATE that I can do the highest graphics in IV but I have to settle for the lowest in V. Seriously if I was a cyborg alien and I played both games and I would bet my life that IV was the successor to V.