I may be just a contrarian asshole, but I don't understand what people are so excited about. I just don't think we have anything in place to make villains work in fort mode at this point. If we had economy and some sort of law system I would be hyped for this arc, but right now it looks like a purely adventure and mostly flavor thing.
My bet is on the villains being integrated into fort mode not even half-assedly, more like quarter-assedly.
-We'll see dastardly schemes featured on fort mode engravings by dwarves who shouldn't know of those schemes.
-Some bards and mercenaries will show up with a profession name of "ringleader" or "mastermind", but those won't do anything.
-Fort mode position holders won't be plotted against unless there was a plot before they came into the fort, at which point all progress stops and nothing ever happens.
-Bandits will be supposed to send ambushes that would work like regular old goblin ambushes, but bandit pops will all die off in year 1 of worldgen with not enough new ones forming, or they will never leave their encampments after worldgen.
-Dwarves will be able to intercept a secret document of some sort (by raiding), but they won't be able to read it, because it won't be a standard book, like with slabs right now.
-We'll be able to send spies, but all info they will bring back is "Smustu Amxudostngosp's real name is Ber Ngosmber" which won't matter in any way, shape or form, since that person would never show up in the fort.
-We'll be able to interrogate captured prisoners, but all they say will be "In 129 Urist Tekkudarban became a shearer in Daggeroil" and "The world is same as ever"
I have absolutely no expectations for the next big update, so I'll either be smug about being correct, or I'll be pleasantly surprised. There's also the third option where the villains will hardly do anything in adventure mode, and will feel like priests in current version, which I hope won't be the case.