No, civ 5 players, the problem wasn't civ 4, it was you. If you never got passed noble difficulty, that is fine. But don't pretend you can judge how simple or deep civ 4 is based on your limited understanding of the game by repeating the same mantras again and again. That civ 5 is a lot simpler than its predecessor is not opinion it is fact. Why does this have to be so fanatically disputed? Just because you like a simple game doesn't mean you are stupid or or anything. Hey, I play Crysis occasionally, that doesn't make me a drooling idiot! Just accept it lol.
Simple and deep are not opposites.
Civ4 is not simple. It is quite complex, and it's fairly deep too.
Civ5 is both simpler and deeper, however.
Civ5 simplified the sliders removing them and replacing them with building maintenance. Your new "sliders" are what you build in a city and spend your gpt on. CHoosing what to build in a city is deeper than Civ4, where you could building spam without a drawback except for...
Health was removed but it was a needless complexity adder. You got less food in an unhealthy city...meh. Any city that needed to be bigger could build health buildings, but those buildings were only needed to counteract unhealthiness, and unhealthiness was only added to restrict big cities, but there was always...
Happiness on a city level is just added complexity. In Civ5 you still counteract unhappiness on a city level (local happiness) but at the same time you have to worry about your whole empire. It's a much simpler system, but with the varying levels of unhappiness from slight (which I consider normal though most or all of the game) to extreme (almost no production, no growth, no ability to found cities, and barbarians spawning in your lands), it's less of a task of spinning plates on 20 different poles and deciding what, if any, unhappiness is acceptable given the current situation.
One unit per hex is deeper, period. In fact, the reason the AI can't handle it as well as the stack of doom is exactly because it's deeper.
Bonuses are both more complex and deeper. Getting 2 traits from a leader isn't nearly as game changing as any one UA.
I could make a civ knockoff where you have cities of 10,000,000+ people late game and have to make every individual person hapy or they won't go to work and cut your money and production, where every solider must be armed, fed, and given medical attention every turn and training would have to be done manually. You have to play WHERE to put every building in your city and decide what it will do. The Goal of the game will be to have more population than anyone else by December 21, 2012, and in each case of battle, the army with more strength wins, period.
That game would be hugely complex, but quite simple with only one obvious goal and combat reduced to a simple judgement of which number is bigger. Civ5 is simpler, but deeper as well.