I'd guess that if this whole 1 upt mechanic wasn't fun, or challenging, or fair they would have scrapped the idea after some testing. That's what I meant when I say I trust their track record of making good games.
As they did with the 'suicide siege weapons'?
When that concept was presented here in this very forum, it took people just a couple of hours to find out that the intended result, making SoDs useless, would be completely missed.
There were many heated debates about this topic, which almost always resulted in the final mantra: "I guess, if this wouldn't work, they would not have introduced it. I will trust the designers, they know what they're doing!"
So let's assume that moving a stack needs same or similar amount of manual work as moving a unit in 1upt. If we have 20 stacks to move in limited stacking and 20 units in 1upt, will it be less manual work to move all the units in limited stacking? I was just saying that it isn't necessarily true that movement in a limited stacking system is less manual work. We need to consider other factors in the system, such as typical numbers of stacks/troops for an empire.
Once again, you try to mix things and go away with it.
Yet, I won't let you go.
Even, if we would agree to your assumption that in a stacked system the number of stacks would equal the number of single units in a 1upt-system (for which there isn't any natural law), then still the stack system would give you some advantages, as the chance to redeploy your units, recombine them after the inital battles and even having some single units taken out of the stacks to pursuit wounded enemies.
As for the AI issue, do you really want a stupid and boring system only in order to ensure that the AI could be good at it? I don't. Also, there has been tons of hex strategy games out there over the decades, why worry so much? It's rather possible that CiV's AI will be rather good, right?
I think, here we may have touched the real issue.
You don't want the AI to be good, which is all fine.
For me as a single player it is important to have a system with which the AI can cope.
Any assumption about the quality of AI decisions we will have to leave for the future, as at the moment we don't know anything about it's strengths and weaknesses.
Therefore, debating it's strengths in Civ5 at the moment is completely moot.
That is perhaps one of the largest downsides to SOD warfare. Since there is no real reason to spread your troops out (since there's no ZOC), there was no reason to have your troops anywhere but the absolute best tiles (hills/forest tiles, across a river, or the most obvious choice, IN A CITY!!!).
First, a city was never the best place for defense.
By hidnig your troops inside city walls, you allowed the opponent to pillage your territory, at least to block you from access of the city's fat cross.
The best defense positions always were somewhere near the borders, behind a river, on top of a forested hill and so on. Not in a city.
There, the enemy was not able to make use of attack modifiers and trebuchets and swordsmen out of a sudden only were worth half.
But apart from that:
I perfectly know about frontlines and 1upt, since I am playing Panzer General since years.
And for Panzer General, the 1upt is fine. It is fun, too.
Nevertheless, a single turn easily takes 30 minutes and more, since you have to be very careful about in which sequence you're attacking, where to move which unit and so on.
And last, the scale of Panzer General maps is completely different from the scale of Civ5 maps.
In the current screenshots and movies we have seen cities as near to each other as just three, sometimes even only 2 hexes.
This will drastically reduce your "operational area".
And given the general assumption that having entrenched frontline units with long-range units hidden behind them will be the superior tactics, this will only lead to WW1 style of frozen trench warfare.
It is not the 1upt per se, it is 1upt at the scale of Civ, what does concern me.
Civ does not provide the right scale of maps for a tactical combat system like 1upt, where you have to "outmanouvre" your enemy.