I wouldn't call it completely unrealistic. All of the units in a stack were in a tile representing miles of land. With the new system, now the units are spread out over huge lands... well, that would be pretty unrealistic. Your army could fill the Iberian Peninsula, while the enemy's army could fill France. Tactics are fine and dandy, but the only way they would truly work would be in a zoomed map, IMO. Now, I have lessoned my discontent (a little) on the OUPT feature, but I still don't really like it. What people seem to keep forgetting is the scope of Civilization. It is a global game taking place over centuries and across an entire globe. Tactics are great for more "zoomed in" games that focus on specific areas or battles (for example, Gettysburg, Waterloo, Normandy, etc). On a global scale, it takes away from the game when it is brought into core gameplay with no transition to a "zoomed in" map. I think that the best thing that will come out of Civ V will be scenarios that represent certain battles (like what I mentioned before) or at least more focused scenarios (like, say, American Westward Expansion... or AWE as I like to call it). But it will be a struggle to maintain a sense of immersion when half the continent is covered with units battling it out.