I guess what I am trying to say is, while Civ III had (arguably) better gameplay, it lacked the jazz. And Alpha Centauri likely excelled in both.
Obviously game play is the *most* important, but emphasis on the Jazz certainly couldn't hurt.
Civ IV is an example of a game that excels in basic game play to an extent that, even though it is one of the most boring things on the planet, its game play is still fun. Civ IV makes no daring leaps, no politically risky moves ... its one true strength was moddability, which greatly increased its shelf-life.
I know Civ IV is a great game, but its also fair to say that it is "boring." Its ... basic underlying mechanics ... say the engine above the engine (the gaming engine as opposed to graphics engine?) is phenomenal. Many great mods were created out of such a *game play* engine.
However, its actual game play doesn't hold a candle to Star Craft ... its the culmination of its Scale and Time-line that push it past Star-Craft on the like-ability for many players. Myself included. Civ games are a semi-persistent world where you can play it at your own pace, and everything has a consequence (although many times, due to AI, not such a harsh consequence).
I'm glad they had the scenarios. Rhyse and Fall was 10x more fun than playing base Civ.
Ironically, or perhaps intentionally, your first time or two playing on even CHIEFTAIN is fun due to the pure scale of the games. However eventually you look for more "challenge" at higher difficulties.
Even then, the player is faced with an intentionally dumb AI that is fed with bonuses, feeding the player's own Megalomania of superiority.
All of this dialogue? To show how Civ IV made boring game play into an Awesome game. I dare say that this is Due to the idea of making one good game as opposed to two Great Games ... But I personally Say that if you have one Great Game, with a Paint Job that pretends to be a good game, it really just supports the one great game, and its still a good game. Meaning that it can have the Art and the Jazz of Alpha Centauri, with the Advisors of Civ 2, and the basic game design of Civ IV, with the unique factions of Star Craft.
Any who, that is my thoughts. Boring Mechanics can make a great game, and more interesting (unique) mechanics can make an even better game. If anything, Fall From Heaven is surely a testament to that.
Even within Fall From Heaven ... the original (2) is a good balance of the simplicity of Civ IV and the added Unique elements. The other modmods tend to choke the mod with a plethora of new elements and bring it away from the Civ IV game design, although the uniqueness of the Factions is still there, so even tho the economy and warfare is suddenly much more complicated it still works ... due to an essence of simple game design remaining, as well as the uniqueness of Factions.
Possible Bottom Line?
Unique Factions, Stay Jazzy, you can simplify Game Design, but PLEASE don't simplify Flavor.