There're a lot of difficulty levels, I don't think anyone cannot win on settler difficulty, so there's always a suitable difficulty level if you cannot win on higher difficulties. There's no point that the "overall level of difficulty" is too high. It'll never be as you can always choose to play on settler difficulty. If settler is too hard for you I'm 100% supportive to make it easier than what it is now.
People just want Deity not to be that easy and exploitable, this ruin their experiences as there's no other "challengeable and un-exploitable difficulties”.
Also even if the developers claim that they fix sth., those fixes are not to the point, the game is still easy and exploitable, making them more disappointed.
The UI, the background, the system are all good, however the balance and the AI are of the adverse.
Something I am trying to say is:
1. Some people want to play Deity because they expect the game will be challenging for them. Some people not. NOT EVERYONE IS A MINIMAXER LIKE YOU!
2. Your skill cap is growing over time. So more you play basic difficulties become easier. I give you my example the First time I beat a certain difficulty level (starting from the emperor ) was quite a challenge. After more and more games it just becomes more routine and less challenging. It is the case of deity difficulty level for a small number of people here. I will never say its piece of cake but it is manageable for me. The more you play more the game becomes less challenging.
3. The game is already complex and quite difficult for new players when you play on Deity you probably won't be able to notice this problem. But if 40% of players beat the game on settler it means half of the possible playerbase was bounced off the game. So yes. There is a problem of overall level of difficulty (or maybe to be more precise complexity for casual players). And the game needs new players and casuals for its own health!
4. For some hardcore players, the game become not challenging over time. Their recept is increasing overall difficulty ridiculously easy for them to get rid of exploits (is selling goods and Diplomatic Favor to AI an exploit or just a catch-up strategy in a early game? You will always have similar ones one way or another). This solution affects everyone.
What can Firaxis do with this problem?
a) add a new difficulty level over Deity.
b) increase general difficulty of the game by pump up AI or get rid of some exploits and balance this with some catch-up mechanics on lower difficulties. Increased production, more settlers etc.
c) totally redesign the game and break the meta and enforce people to explore it from the beginning. But this is not a card game where you can buff, or nerf few cards, rotate some set from the game and add a bunch of new cards. So we shouldn't expect this kind of meta shaking.
I don't think it is a possible and elegant option on the table in near possible future different than adding a new difficulty level over Deity. If someone wants to catch a rabbit feel welcomed. Just say clear: I need more challenge rather than cover behind talk about exploits, balance etc.