The one thing that makes it a bit dull for me, with my gameplay style, is that there is absolutely Nothing to do besides wage war.
Now, i Never ever waged war in Civ4+all exps, i'm dead serious, never.
I just played the culture, diplomacy, religion and trade game, and expanded, tended my cities and llllloved every single hour of it. Over and over again.
Now in Civ5, its like. Yeah, the combat is awesome. Yeah, for the first time i do like the combat in a civ game, but... I dont WANT it, you know? I dont want to be forced into it. This is a civ game, not Starcraft 2 (that i also love, but just as Starcraft shouldnt be like Civ, Civ shouldnt be like Starcraft).
I feel like there's nothing but combat in Civ5. You have to massage and sausage-suck the AI's to ridiculous lengths to keep the peace, you have to build a large army, to keep the peace, that's ridiculous.
(if you think its realistic, think again and take a look at real life) Its ridiculous that the AI plays to "win". And hugely immersion breaking..
I mean, play to win? Win what? Win the world? Win the future? Win what?
Oh wait, win the game. Game.
This brings to mind Sid Meier's talk on GDC a while ago, about the secret agreement between the develper and the player to suspend the disbelief, the devs part is to design the game in such a way as to provoke the player into willingly decieve himself to think its real, to extend the gameplay and immersion.
Then comes Civ5, as if it hadnt listened to Sid what so ever, and the AI's magically want to win the game, the concept we were supposed to agree on to keep hidden, we were supposed to pretend it was a world of different civilizations and nations, growing and dealing with eachother in various ways.
And here comes Civ5 and just blatantly and incredibly clumsily announces "I WANT TO WIN!!", spits in your face and declares war because they settled a city next to your capital, because the AI predicted ten thousand years in the future and decided that the threat of nukes is too great, its best to annihilate the player now with the bowmen (and fail).
I mean what else is there to do to keep the immersion?
Theres no diplomacy, you cant do anything. The only reason to go into the diplomacy window is to declare war or propose peace, and to trade gold or +5 happiness.
(call the resources whatever you want, they are all just a +5 happiness stat anyway)
And the entire Pact of Cooperation is only there as a MEANS TO ENSURE FURTHER TRADE, but.... The thing is, there IS NOTHING FURTHER TO TRADE... So, hence it loops back to the Pact of Cooperation being rendered useless. It blows my mind how such a common sense conclusion didnt enter the designers mind.
This applies exactly the same way to Pact of Secrecy too, the only purpose of the Pact of Secrecy, is to worsen relations so you can declare war "easier" in the future, but the thing is, there's no "easier" way to declare war anyway, just hit the declare war button, hence it also loops back rendering the Pact of Secrecy utterly pointless as well.
If they worked on having a big normal tech tree, they could keep tech trading, and then there'd be an actual reason for diplomacy, and an actual sense of excitement when meeting a new civ as in civ4, rubbing your hands wondering what goodie techs they have for trade.
Instead of as it is now, you sail across the ocean, discover a new continent with Ghandi on it, and.... Well.. He has cotton and some gold. Wow. How much fun. +5 happiness again. Next.
I'm guessing that like me you probably didn't really enjoy part of those 59 hours either.
Yes, ciV is a big miss for me too yet surely it's no MOO3? Kind of like Spore - massive disappointment, but still somewhat enjoyable in some small, basic way. 
MOO3 was frustration incarnate and failed in every possible and impossible way. 
