Oh I know its certainly possible to see invasions, but honestly I no longer feel a 'threat' from distant Civs as I once did. I can routinely turn down their requests and demands and run relations into the ground and its very rare for them to DoW me. In the past, I knew that even if they wouldnt be overly successful, even a limited war would slow me down.
Okay, I understand what you mean there. I was expecting Mehmed to DoW me in the last game -- I was on the cusp of a spaceship win, and according to the power graph he was stronger than the rest of the world combined. I had a huge navy; he had a huge navy and army. If he'd been able to land in force on my home island, he might have stopped the spaceship win (although I spread out the parts-building to several overseas holdings, so maybe not.) Still, the wiser AI decision would've been to attack me even if our relationship was "pleased" (versus his "annoyed" with Korea -- who was also building a spaceship, albeit slower.) I breathed a huge sigh of relief when he went after Korea. Mehmed was right across an 'English Channel' sort of body of water from me, whereas Korea was halfway around the world.
I suppose it made sense to the AI, since our relationship was cordial, and everyone seemed to hate Korea....
I haven't seen it either in 3 games played (although I havent done a lot of long-term sieging either...usually one turn of bombardment and then the overrun.
I ended up doing a rather longish seige of Washington when I fought the Americans in the last war. (Just didn't bring enough troops in with the first wave of galleons.) There were some troops shifting around, but nothing major, and certainly none came out of Washington that I could tell. Roosevelt did try to hit me with some seige units (two or three cats at a time, which was good,) but there's only so much that catapults could do against grenadiers and rifles. Once Washington fell, it was just a matter of time before his other three cities went.
ALso -- I am finding that taking on "protective" civs is now doubly annoying, since the AI now spams defenders, and all of those guys are already pretty buff...
I am still playing on Noble, for whatever that's worth. I have so far won a domination, spaceship, and diplomatic (a "true" diplomatic, not a domination by-UN win.) Going to try for a culture then move up to prince....