Why does it matter that buildings are single purposed from a strategic point of view? In fact making a building dual purposed reduces the importance of your decisions. What's the point of having to decide between a science building or culture building first when you can build one that just does both? You talked about interspersing a forge/factory to speed things up. How is that different from throwing in a workshop/factory to do the same? Other than now you don't get the happiness bonus from the forge so you really have to think about if its really worth it to you. If you want an extra bonus from your silver and gold then you have to build a mint too. When previously you might have built the forge for the happiness and the production bonus was just a nice perk. You don't get everything handed to you on a silver plate rolled up into one nice little package. Your decisions actually matter more now since you are not getting side bonuses that cover your weaknesses for you.
Better AI would use research treaties properly themselves nullifying this advantage. Any advantage you can gain from research treaties can be equalized by an AI if its programmed right. For example maybe they would only sign an agreement with you if they are ahead of you in tech. Then they would actually get more out of the agreement than you would. They could also be just as active in trading with each other as you are with them. Again, the failing is with the AI.
How are they auto-pilot decisions any more so than in IV? Your production city might still need to build a culture building so you can get more tiles to work (or even just to unlock more SPs) for example unless you plan on spending all your cash on buying tiles. How is that different from it building a library like you mentioned above?
I also find it funny that people seem to forget that IV had some sequential buildings as well. You needed a library to build a university, an observatory to build a laboratory, a forge to build a factory, etc.
If you decide on going for a cultural victory and ignore other aspects such as science and unit production a good AI should spank you back to the stone age. In order to stay competitive and not risk being destroyed by a decent AI (or human player) you would have to play a more balanced game. If you play a game against me and you build nothing but culture buildings in all your cities, and ignore science, or build all the science buildings and spend all of your cash on research pacts while ignoring unit production I can guarantee you are going to lose all of your cities. You have to play a more balanced game and not fall too far behind in any one area. A good AI should be able to do the same thing. Instead, against the AI as long as you have 2 or 3 units to defend you are perfectly safe. So now when it comes to that point where you are deciding to build cultural building number 3 or throw down a library so to not fall too far behind in tech your decision might actually matter. Instead of not mattering at all like it does now because the AI isn't going to punish you for falling behind.
Again, this is only because you can ignore other aspects of the game relatively safely. Yes you might want to spend all your SPs on getting you closer to that cultural victory we have been talking about. However if the AI is attacking you with a scary attack force and has all the unit upgrade SPs can you afford to ignore them yourself? Currently yes. Because no attack force the AI can put together is scary. If the AI were any good then maybe not. If you were getting slaughtered because the AI's units were getting double exp, additional bonuses for being near each other, and bonuses for attacking when wounded you might have to think twice about spending that next SP point in the piety tree.
Actually no. Just as an example, city-states are just as multifaceted. They are involved in diplomacy, commerce, and science as well. Everything is there in the new mechanics just different. Of course the AI is crap at dealing with them properly though.
I have 3 excess happiness. Do I let my production cities have them so I can work more mines? How about my GP farm to run more specialists? Or maybe I let my trading post cities grow so I can get more gold? You have full control over where your population goes now. That opens up so many more options.
If you are running at +50 happiness you aren't expanding enough (small empire cultural strats aside). That would be like having a happiness cap of 10 in CivIV but never growing your cities above size 5. You are wasting quite a bit of potential. However, because the AI is so terrible it is not punishing you for it. If you are going for a small empire cultural strat then yeah happiness is going to be much less of an issue, but there are other downsides to that kind of plan (low science, low production) that the AI can take advantage of if it didn't suck.
Again, if needing more happiness is rare then the problem is you aren't expanding enough to reach your potential population cap and the AI isn't punishing you for it because it sucks. Try that against a good player that fully uses their happiness cap and see what happens. Also, if in addition you have enough gold to buy everything you want then its again because you don't have a large enough military upkeep costs and the AI isn't punishing you for that either.
The problem is you see being able to do whatever you want and being able to ignore the other aspects of the game as being a fault in the complexity of the decision making process. In reality its because you are not being pressured to make good decisions. Try some of what you are talking about against good players and I can guarantee it will go badly for you. It only works against the AI because the AI sucks.
, or more accurately, didn't let themselves be challenged by the game.
