That's not true in my case. I'm perfectly content to play at whatever skill level offers the experience I find enjoyable in either game. I don't care what anyone else thinks, and I get my competitive kicks in other ways (Counter Strike, CoH, etc. ) If I end up a difficulty or two higher in Civilization 5 that really isn't a plus or a minus to me. I'll not assume that you don't like Civilization 5 just because it isn't Civilization 4 if you agree not to assume that I don't merely like it because it hurts my feelings less or something. Fair enough?
So, let me explain a bit more what I mean. You said that winning the game on difficulties higher than you felt comfortable was a chore. It sounded like you thought this was a negative to civ 4 that was not true in civ 5. Was I somehow off base there?
But... Have you beaten 5 on Deity yet? Would it also feel like a chore and not be fun? How then is that a difference, except in the sense that the level where you could 'win and it not be a chore' was a harder labeled difficulty than in the previous game?
If you want concrete reasons why I like Civilization 5, I'll toss a few out there.
Empires can be "Wide and Flat" or "Thin and Tall" Think the typical Gandhi strategy versus France cracked out on Liberty. The global happiness actually gives me a reason to have 12 towns with a population of two instead of 3 big cities. In Civilization 4, any empire that can support huge cities can make *all* of their cities huge. Podunk Ohio strains your Civ4 infrastructure as if it was New York City.
Ghandi actually makes better bigger empires than other people too

. I know what they are going for here, but it isn't actually strategically true in this game. Civ 4 had a LOT more knobs to tweak for each civ. Philosophical leaders played differently than aggressive ones. I don't really think you can even really support an argument saying there are more varieties of strategies in civ 5, though I'd be curious to see a real debate about it.
I agree that in civ 4 all cities can be as big as the biggest city, given time to grow. But not all could have a heroic epic, or a national epic, or a westpoint. The inclusion of certain types of effects, and national wonders all over the place allowed for city specialization that you don't get as densely in civ5.
I have more reason not to cram in any old building a feel like. While any decent Civ4 player knows that it's often better to grab some extra soldiers or even produce wealth than build every last building in a city, you still tend to build improvements in a "fire and forget" method. Yes, there is an opportunity cost in hammers, but it is not a game-long gold drain as in Civ5.
I don't think this has really changed. You are saying maintenance costs of buildings deter their production, so increase viable options? I guess that's true. But I think the value of buildings, and the very limited time scales in civ 4 were just as important. Opportunity cost is a far more interesting mechanic. Even then, the hammer costs in 5 are much larger, so I don't even see that as a difference.
The slower hammer rate tends to give more emphasis to units already in the field, and the higher base movement rate means that your opponent is less likely to be able to simply spam defenders. They *can* do this, but it will cost an aircraft carrier full of gold bars.
Random aside: I actually purchased an aircraft carrier in my last game, funny you should mention it. Hammer rate is also very... odd in this game. You can spend a lot on workshops and windmills for little gains, but if you just go for communism and railroads you end up beefing up your production much more meaningfully. Also, automated worker placement doesn't seem to understand that production is important too.
I also hate some things about Civilization5. The leaderheads are, while technically superior, artistically inferior to the ones in Civ4. Trading posts are ugly and conceptually strange compared to cottages. The audio isn't nearly as good. The game is unnecessarily bloated performance wise. Important information is sometimes difficult to reach in the UI. The 'pedia is a dripping, blood soaked abortion.
The leaderheads are mind boggling. They spent soo many resources on them, yet they are almost always just boring to look at. Talking to Alexander on his horse is all immersive the first time you do it. Subsequent times you start wishing the diplomacy was overwith already.
I think that agreeing to respect each other's opinions can only make this forum more civil. I'm totally fine with the fact that you don't like Civ5, I just don't appreciate being insulted because I do.
I think in the end, everyone is losing. The game is mediocre in the overall, so only about half of the community (or some other percentage) is TRULY enamored with it, and a good chunk are really angry about having paid 50 bucks for it. While each side can have their opinion, if the game had simply not felt half-finished, and had been better balanced (game system wise) I think we'd all be a lot better off.