I agree that it's very annoying losing loads of troops like that -- and it's too hard to know what is the right number of troops to use -- too much of a gamble at the moment. In those options listed above, the "teleport to palace" option might be the most do-able, even if it isn't the most well liked. (I don't like it, but it's better than losing 20 mech infs to a culture flipping size 5, Iron Age city). I think delaying the next turn's unit points sounds too much like a special case implementation, and how can you be sure that they'll be far enough away and for long enough for the defending Civ to effectively garrision its recaptured city. But, in fairness, at least they'll be away from the city and mostly alive. Yeah, I think it'd best if not all survive -- especially with methods like food/water poisoning, I am sure 1,000,000 bitter citizens could clear a large chunk of a hostile army if they were determined enough. It may be even better if there was a certain learnable trick to it -- such as if you have a size 7 city, you'd need 14 units to defend it (ie city size * 2). Put in a bit of random too, just so it doesn't always work as you expect. Hmm... I don't think anyone's stumbled on the perfect solution yet... but I could be wrong.