1. Quality of life - there is no filter to see which cities have which structures. What I end up doing is renaming all of my cities, e.g., "Roma - DT" to indicate it has a Defense and a Trading Post.
2. Explain loyalty mechanic better to players. My experience: I have cities that flip and take a large chunk of territory as well as absorbing my surrounding elite units (!!!). This happens early in the game before I have Civil Service (I like to play the Germans...). Result: I just pillage all captured cities and make new cities with my own nomads. Effective but not satisfying.
3. Influence right now is a very powerful mechanic that is not deeply integrated into the gameplay in proportion to its power. That is, either I do influence on an opponent city, and opponent can do little in the way of defense about it, or the same on me. The mechanic should be more transparent (what exactly does 'obedience' do?), and the mechanic should be more fully integrated to game given its power. Right now, it feels to the player like a late edition add-on to the game.
4. Here is something that feels like an exploit: offer most AI players just about anything as a "free offer" (e.g., 3 food), and the AI will offer you the kitchen sink in return. At least this has been my experience in about 10 trades in recent game (I just discovered this little advantage --- which I am calling an 'exploit' --- it would be good if in fact this is by design, so I'd feel free to use it with abandon).
5. Here is something that I think might be a bug. It seems like "Games of Skills" comes up much more often that the 1 per 5 years as stated in the tooltip. If you don't know, for just 10 gold and 10 food, you can get yourself a free military unit, and often this unit is not one you can make. Great for Germans who need a unit that works on grass and plains!
6. The tech economical city seems not well balanced. It costs a lot and it does just a little. On my city of population level 8, I get back 0.25 coal per turn, compared to a coal mine that produces 4.0 per turn. I'd have to have lots of cities of population 8 to ever get excited about the economical city.
7. Some folks have commented that "food is too easy" as a resource. I agree in 50%. At beginning of game, it is challenging (so I disagree). Try the Germans! It's challenging for small countries without rivers and grasslands. It's challenging for countries without cultivation. In other cases (so I agree), it's no longer challenging. But you can always trade away 3 food to all AI players for gold, coal, stones, .... etc. as a "free offer"
8. I have a suggestion for enhanced replayability. Right now, there is the Rome scenario with a fixed map of resources and there are the completely random maps. Let's have an intermediate point: offer an option in the Rome scenario to randomize a little or a lot the (i) types and (ii) positions of resources on the map. To be clear, the base Rome scenario should continue because there are merits to a fixed map, but also that same scenario could be given increase replayability with the options mentioned of (i) and (ii).
9. For custom maps, allow an option of scaling science costs by square. Right now, all science late in the tree gets discovered "too early" on huge maps because of so many cities and so much science. (Let's be honest: everyone just plays the game to conquer the entire map --- forget about other forms of victory.)
Again, I love this game. Above is my list of "how to make the game even one that I love more."

