@Foltest 1) What? Wrong. Did you never succesfully stop a stack of Doom with barely a fifth of the defenders, but them being bunkered in, supported by thick walls and artillerly, and with constant reinforcements trickling in? 2) The one unit per tile nonsense utterly destroyed the strategic element. You know, economy. It is much less necessary to have a constant supply line, because the units are more like Warcraft 3 heroes than Starcraft 1 marines. I imagine everyone who says OUpT is superior has never had the quite patrician experience of playing a Paradox grand strategy game (hint: it has "stacks of dooms". Precisely due to these soft-stacks it is superior in combat mechancis to both Civ 4 and Civ 5)

Actually, the AI knows it is better to build a fort on an important resource if a nearby city cant use it. Forts give you access to the resource,just not the increased production That way, it is at least easier to defend the copper/iron/horses/oil/uranium, where a mine would do nothing.

Yeah, stacking removed any combat strategy in the game. I can't really tolerate it, it's so bad, to be honest.

Units can stack being the BAD part of Civ? All you need to do to counter it is build what, 1 or 2 siege units for every 10 other units they have? It's easy. Plus, No stacking was a mechanic that made siege weapons not a pain in the ass to use, and made them more useless than in Civ 3