I've now completed a couple games with the new Civ V patch (v. 126.96.36.199) and feel like I can make some informed comments. Overall, I am very pleased. The game is significantly more challenging, and a number of balance tweaks were introduced that make the civilization-building process more rewarding. Obviously, there is still room to improve, but Civ V now ranks among my favorite strategy games of all time.
Some details: Prior to the patch, I had played three games to completion, two of which were on Emperor difficulty. I won all of them easily: one via culture, one via diplomacy, and one via space-race. The wartime tactical AI was atrocious and could be outmaneuvered by a single powerful horseman.
Since the new patch, I have played one game to near completion on Emperor difficulty as China. I went for a cultural victory but it became clear to me around 1900 that I was going to lose to Hiawatha, who had researched the Apollo program and was way ahead of me on tech and military.
I dialed things back a little to King difficulty and played as Russia. Definitely my most entertaining game of Civ V yet. The screenshots I include in this post come from that game. Standard map size, continents, 8 civilizations, standard game speed, no mods installed. I eventually won a space race victory but Napoleon was leading by points for the majority of the game.
Rather than bore you with an AAR, here are some of the positives I noted in these patched games:
1. AI is better at "bringing it" in warfare and stock-piling defensive troops, especially if it has a tech advantage.
In my 1st game, I mentioned that I realized in the early 20th century that I didn't have enough time to complete my 5 social policy trees before Hiawatha completed his space shuttle. So I decided to quickly research the Manhattan Project and try to disrupt his progress with an atomic attack. As soon as I declared war and lined his border with my troops, he responded swiftly and strongly. He had a large military advantage at that point in the game, and within 10 turns he had already conquered one of my cities and was marching towards my capital. Nuking him had little effect.
2. AI tactical military decisions have improved.
A couple things I noted here. First, when attacking AI cities, it knows to focus its bombardment and counterattacks vs. your siege units. Second, if it has researched Flight, expect to be air-bombarded constantly while in its territory. Third, it is making better decisions about whom to attack with what unit. For example, in my 2nd game as the Russians, I rushed to knights before attacking the Ottomans to my south. After I invaded, I noticed he had a number of pikemen defending his cities and he used them quite effectively against my knights. My longswordsmen and siege units were much more important in victory than my knights. The screenshot below shows him defending one of his cities with a pikemen poised to attack an incoming knight, and a knight ready to charge against a siege unit. Fairly clever.
3. Unit promotions don't occur until the turn after the unit earns the XP.
This is a welcome change, since previously you would almost always heal your units, making it very difficult for the AI to kill off your wounded.
4. Mounted units and tanks get penalties vs. cities.
I love this change, since it really forces you to research and produce infantry and siege units to support your cavalry and tanks. You can't simply horse-rush an opponent anymore - their cities will hold you off indefinitely (especially with the improved city-healing).
5. Diplomacy is improved, but still a little wonky.
I like how the AI's now reveal why they feel a certain way about you (see screenshot below). And it is possible, albeit challenging, to maintain positive relationships with your neighbors for long periods of time. Denouncements throw an interesting twist into the game. In my game playing as Russia, I was denounced by the Persians because I founded a city too close to their borders after promising them I wouldn't. This ruined my relations with the Ottomans, who previously held a neutral attitude towards me. This made it so that I couldn't effectively trade my luxury resources early in the game (since these were the only 2 civs I was in contact with), which made happiness and cash accumulation very difficult. I really enjoyed this challenge, right when my empire was poised to blossom.
There are times when the AI will denounce you for reasons you can't understand, and it can be quite difficult (and therefore frustrating) to repair relationships over the centuries. Given that there must be a rule "under the hood" that the AI is following to determine its denouncement, I suppose I'd appreciate even more feedback regarding their reasons. For example, India might denounce me not because of anything I specifically did to them, but because they've been bribed to do so by another civilization. From my standpoint, it appears random - but it would be useful if India said something like, "Some of my allies have convinced me that your foreign policies are threatening to world safety."
6. AI's seem better at managing their economies.
This allows them to engage in far more research agreements, which they will spam across the entire game. If you don't pay attention, you'll fall behind in the tech race quickly because of this. After taking over a number of enemy cities (and puppeting them), I noticed that most AI governors were set to maximize cash. If this is the case across the board, it's slightly problematic - since at least one or two cities should be specialized for production.
In both games, I encountered civilizations that had acquired massive fortunes. See Napoleon's screenshot below. I suspect this money is being accrued via conquest and then raping enemies in peace treaties - a game mechanic players have been known to abuse as well. This again suggests that the AI is "doing well" in some respects but it also indicates that the AI doesn't know how to spend its surplus. With this much money, it should be very easy to pay off every city-state in the world and win a diplomatic victory - or insta-purchase dozens of science buildings for an unstoppable tech advancement.
However, I didn't get the sense that Napoleon was going for that. He had conquered most of the world, and was far ahead of me in points. It was the 20th century and I had researched the Apollo program. I assumed he was going for a military victory, and he was within reach since only he and I had not yet lost our capitals (see screenshot below).
If he had sent his entire military strength against me, he could have crushed me in the late 19th century. However, I was across the ocean and the AI still seems very hesitant to engage in wars on different continents. Also, I believe he could have researched the United Nations, payed off every city-state, and won a diplomatic victory before I finished my 1st spaceship part. But he just sat there, threatening me, until I won the game. This was the most dissatisfying aspect of the game, and indicates that additional work needs to be done on intercontinental invasion AI.
7. Some random notes.
I like how science production is now more dependent on the size of your cities, making larger cities more valuable. Also, it's probably a good thing that libraries don't have a specialist slot anymore, since Great Scientists are very powerful in the early game.
I love the idea of a revolt happening when your happiness dips to -20, but I doubt that's ever going to happen to me or the AI's. I think this should be tweaked to something much more threatening, like -5.
I'm not sure how I feel about not being able to defer social policies. Previously, it was an interesting instant vs. delayed gratification choice. Do I take the bonus to happiness now, or stockpile and wait until the Renaissance to burst my way through the Rationalism tree? The biggest advantage I can see to the new system is that now we (the player) are forced to behave like the AI's, since they never seemed to weigh the advantages of stockpiling. Regardless, the option can be changed in the set-up menu if you prefer the older system.
The AI is engaging in a bit too much ICS, settling small cities in inappropriate locations.
Overall, as I said, I'm very pleased. I find it interesting to read the various forums, on 2K and Steam, and hear so many people complain about so many different "stupid" things the AI's are doing. You begin to realize that individuals are having greatly varying experiences: for some, the AI's are overly aggressive and don't leave you alone - for others, the AI's are too passive and allow cultural victories without nary an invasion. Such variety, I suspect, is suggestive of a deep, complex, and highly replayable game. I look forward to subsequent patches, some creative mods (Dune Wars for Civ V please!), and big expansions.