There's a few factors here. 1) When the AI can achieve it and, as the player can, achieve it too quickly, then it is just as imbalanced. Our game is down to one other major contender in the whole globe and it's still the ancient era. When we come to blows with that contender and one of us gets the upper hand over the other, the game's pretty much already over. They've stomped their entire continent already and are double our point score. 2) This game is taking place on Size Matters where many strength limitations, particularly in offensive efforts, for the standard game can very easily be overcome. To balance this out, the AI needs a stronger defensive AI (not stats so much but response planning). I also believe that ongoing training xp is going to be necessary to really balance it out as well. 3) So in the main game I don't think that defenses are TOO strong because if done right defenses needs to be capable of trumping even great offensive campaigns so that the runaway is much more difficult to achieve. However, I don't think it necessarily needs to be made any stronger... I think the balance is there. Though I do think the defenders still need some better response AI strategies overall. So is this to say that Size Matters has been found to have a flaw? To some extent the answer is currently yes because after my recent AI adaptations to size matters, I'm finding that it puts a lot of favor in the hands of the invader since cities are much harder to build as strong a defense as they need to have to handle the strength of oncoming powerful stacks. However, if the AI were taught to have one or more very strong mobile defensive stacks, it could resolve the problem and would make things a bit more like the real world. If an army marched into Las Vegas NV and we had to make a stand with nothing but the local National Guard, we'd be toast pretty quick. But in such a scenario, the US Gov would be routing defenses to the site of the battle so as to make a stand. The AI needs to consider this strategy as well and original CivIV combat arrangements never enforced the need for this much. As for your suggestion to rework the longest game speed... I think those that favor that game speed would be the ones to defend it or not. I don't personally want the game to take THAT long myself either but some seem to be fans. Those are the ones I'd listen most closely to... IMO gamespeed adjustments should all be in equal ratios to one another for the most part so that a longer gamespeed just means a bit more unit movement can take place but otherwise the game should pretty much pace the same throughout the eras.