I will add my thoughts from the poll thread:
One unit per tile sounds like micromanagement hell.
Imagine taking civ4 and making it so you couldn't select multiple units at the same time, and had to move every single unit individually.
Imagine making it so that every unit that won a combat was immediately eliminated on the next turn, because it was weak, and you couldn't have another unit shield it.
Imagine making it so that if you wanted to move a particular unit to the front, you had to carefully micromanage a clear pathway of units out of the way.
Think of the classic puzzles, like the tower of Babylon, and how many moves it can take in order to free up the space to move an object from A to B. You have to move the one currently in B to C, but to make space for that C has to go to D, and to make space for *that* D has to go to E.
etc.
We definitely have to get away from the Stack of Doom mentality, but a strict 1 unit per tile limit will be hell unless the number of tiles is truly vast. Which doesn't sound like much fun either, especially with units that have 1 tile movement rates.
and add:
1. I like the idea of limited units from resources, but severely hope it isn't 1:1. 4-5 cavalry units per horse resource sounds fun, 1 sounds horrible.
2. I like the idea (slightly alluded early in the thread) of increasing stacking limits based on tech. Maybe one tech per era could improve supply lines and allow an extra unit to stack.
3. One unit per tile would place a *huge* need for AI improvement/development. SoD is easy for the AI to handle, it can be really stupid and still pose a threat. But intelligently using fronts of units, and support, unit placement etc. sounds very tricky, and if they mess up then the game will kinda suck.
4. Another issue with 1-unit-per-stack: how do you withdraw damaged units through your lines without huge micromanagement?
5. The simple best solution for stacks is not to hardcap the stacks, its to increase the value of their counters. Create a lot of ranged bombardment collateral damage units and an AI that knows how to use them, and you'll provide strong incentives to spread those stacks out.
Civ4 tried this with collateral damage catapaults and such, but still largely failed, because you had to suicide your siege to do any damage.
6. I really worry about unit preservation. How do you conserve/promote units if you can't protect an injured unit with a full-strength unit?
7. I like the idea of using Generals to have more powerful units to punch through enemy lines.
It sounds like they might be trynig to use the strategic layer to really replicate tactical combat mechanics. I can see a lot of potential here. Applying heavy force to open a rift in enemy lines, allowing you to turn the line and attack from multiple angles. Turning a flank allowing you to envelop the enemy and roll up the side.
Place the archers on high-ground, use the cavalry on open-ground, etc.
8. I am a little worried about ahistorical nature. Big fronts of units are really a 20th century phenom. Before then, most wars really were armies wandering around, manuevering for position, and then big battles of the entire armies. [Saw the mongols mentioned, but they're an exception, as a hugely mobile force with more horses than everyone else put together.]
I would love if Civ could somehow incorporate some of the value of strategic manuever.