1upt introduces the same problem concerning space, which was largely absent until now. A tile represents huge areas, and of course you can have lots of units there. In Civ3 you had the phenomenon of warships shelling Madrid out of the Mediterranean, but this is gone, gladly. Soon, however, we will have units shooting across whole provinces and battles spanning out across continents. But what you need to span out is the war, not the single battle.
As a recent convert to the flexible-scale way of thinking (see
this thread), partly because I don't think the developers are going to change this, I think the best way to think about it is the following:
Civilization is a large-scale game and a small-scale game, but (unlike e.g. Rome:Total War) both scales use the same map. This requires the player to be flexible in imagining what the map represents.
- When placing cities, considering trade routes, arranging the general deployment of forces, etc., the map is large-scale, each plot covering a huge area and the whole map representing a planet.
- When engaging in battle, bombarding cities, sending reinforcements for the next turn, etc., the area around the battle, on the same map, is now suddenly to be imagined as a much smaller place, for example, just the few hundred metres outside a city's walls. And the turns (though the date may still increment by 10 years or so) are to be imagined as something like days or weeks.
When the small-scale battle is over, you go back to thinking of that area as a huge region, and the turns as 10 years long. The battle appeared to span a thousand kilometres and 50 years, but you can think of it as having taken place somewhere in that area, and at some time during those decades.
Kind of messy - I'd prefer zooming into a separate tactical map, or having no tactical level at all - but the way they are doing it (1upt) allows a tactical level AND it keeps the game mechanics simple.
Now, I think there would have been a far better solution for this than 1upt, namely introducing supply requirements and supply lines.
Part of what you suggest is already there in Civ4: it costs more to keep units in enemy territory than in your own territory.
I agree with you though, that, if the objective of the developers was to weaken the SoD strategy, they could have used other ways. I like your supply-line idea, but I suspect that many players/developers won't (1. additional compexity, 2. can the AI deal with it?). My preferred approach would be simply units talking a certain percentage of attrition when in enemy lands (as no supply line is good enough to avoid attrition), but I think that this also would not be well received.