if the end goal of 'solving the same problem' negates the value of complexity, then the CBP is intrinsically without value, as all changes made in some way make the game more complex.
Absolutely not true! Many of the changes that may been made are clearly documented.
The changes to most buildings....in the tooltips, easy to understand.
The policies....in the tooltips, easy to understand.
Investment....explained in the tooltips, tells me how it works.
While the espionage system is more complex in certain ways, the fact that the city potentials are now always visible I think has made the system more interesting AND easier to understand. Put spies in cities with big potential = benefits. Simple to understand, yet because those values change more often it makes the system more dynamic.
The CSD system is very different from the core game...but still easy to understand. Build units....and the units tell me exactly how much influence I will gain. I know what units I need, and how many I need. I know that to get more units I need more paper. I know exactly how much paper will get me more units. Very simple.
The happiness system...is not simple. The fact that luxuries scale is mentioned...how they scale is a bit mysterious. The fact that building a building will sometimes fix happiness, but sometimes not....adds to the mystery. The fact that happiness thresholds change from game to game because of how other players are doing...makes it mysterious. Now....if that complexity gives us great benefits than so be it, but the argument being made is the payoff isn't worth the cost like it was in other subsystems you have adjusted.
The only parts of the new system that are pretty simple (and probably why they are my favorite parts about the new system) are the isolation and the burning lands penalties. As far as why I am getting 2 unhappy or 5 unhappy for isolation....I have no idea. However, I know exactly what I need to do to address it, and it works every time. That makes it simple.
Edit: I realize that there are two notions of complexity, and I want to ensure I am capturing what I mean.
Complexity = More to learn. In this way, yes the mod is more complex. There are things people have to learn compared to the base game. I think this complexity is generally ok...although changes should always have to "earn their place".
Complexity: Action doesn't translate into a Direct Reaction. This is the area that I think the happiness system struggles with. The Investment System is very direct. Spend X Gold, Get Y hammers. CSD. Get X diplomatic units, Get Y Influence.
If I get 5 luxuries I will have....um, 6~7 happiness? Maybe?
I have 5 cities I will have....I have no idea how many unhappiness.
If I build a building to reduce illiteracy it will.....maybe reduce unhappiness, maybe.