RTS Wargames
In an RTS, they drastically simplify issues like food, happiness, and research. Food is strictly there as a limitation for what size army you can make. There's no such things as happiness or unhappiness, your soldiers will march into battle one by one getting mauled down if those are your orders. And research is strictly a question of upgrading your weapons.
Of course, by simplifying these issues, an RTS can afford to be a bit more intricate with combat. If an RTS is balanced properly, there's a complex system of relationships between the units, with no obvious "best" unit despite having a dozen or so unit types for each player. "I'm going to focus on building tanks! ... but what if he has lots of air units? My tanks would be screwed! Maybe a tank and anti-aircraft combo..."
... not to mention that the number of troops are much more fine in an RTS. One soldier really is one soldier, and thus, formations can be more complex.
Learning from RTSes
Note, you must be well aware of the assumption that Civilization 4 will be equally as complex as Civilization 3. For everything they add, they have to take something away. For each game play lick they make more sophisticated, they have to simplify another game play lick.
I think Civ could take this kind of route... To make room for new military concepts, you'd drastically simplify other concepts. You could drastically simplify cities as centers of military production. No more temples and marketplaces, but more of an RTS model where there are 4 upgrade stages for your "City Center" (Ancient, Middle, Industrial, Modern). Research could be overhauled where every technology was a military technology, getting more unit types out of the deal.
But I think this would be a disaster.
Civilization is not a war game. I think you could, theoretically, make it the best Turn-Based War Game out there. But it would still be a Turn Based War game in a market of Real Time War Games. When it comes to war, a broad audience demands fast action, which Turn-Based cannot provide. Civilization would be called "a slow version of Age of Empires".
You could complete the final step for this hypothetical "Civilization War Game" and make it an RTS. But then you ultimately lose ANY competitive advantage that Civilization has over other strategy games -- both turn based and real time. The only remaining advantages are (1) Civilization's name, and (2) Civilization's scale -- spanning from the first settlements to the information age. And even #2 is being done by a few RTS War Games.
Without a competitive advantage, your product will make no money.
The Real Lesson
Civilization ought to emphasize the things that no other game is doing. That's why making peace more sophisticated makes so much sense. There ARE lots of people who would love to brag about dominating the world through culture, or diplomacy, or economics.
But to bring it back full circle, about combat strategy...
There IS hope for Civilization to make improvements to combat, too. But it can't be anything that adds another layer of management to combat.
That still leaves lots of things, including three that came up already in this thread.
- Cutting out railroad teleportation (e.g: capacity system, or 1/9 movement RRs)
- Multiple phases (e.g.: building phase, movement phase, combat phase)
- Combined arms (e.g.: bonuses when mixing unit types in a stack)
All of those involve players doing BASICALLY the same things they did in Civilization 3, and still making the same decisions about what to build and where to move. Just a bit more thought for those smart enough to take advantage of them.
