I couldn't help but note the difference between the historical figures number and the number of dead; this should give the sort of historical figure population. If memory serves, in my Large world, it was about 18000 people, whereas in older versions it was about 2000 for a comparable world size. I could be wrong on this, but it might explain some world gen speed decrease. It might also explain the titan genocide.
EDIT: I noticed in the ask Toady thread or whatever it's called that someone said they'd noticed lightening fast bandits running over to them and masacaring them after taking one step. I don't think this is a bug; it just happened to me, but I think it was supposed to happen.
See, I had just taken an arrow to the leg, which snapped a tendon, sending me to the ground. The enormous group of bandits that had jumped me had quickly wiped out my army of followers (I'd just spent about half an hour recruiting them), so I equipped the world's only crutch that I'd found in some lair, and stood up. Standing up was okay, but I took one step, and the whole bandit group ran over and started laying into me. I'd forgotten that having a crutch slows you down based on your skill, and this was the first time I'd used a crutch, so I had no skill. Therefore, I'd handed many turns of combat to the enterprising elf bandit who'd killed me by moving one step. Irritating.
Still, it would be nice if I could travel the wilds a bit. These bandits are just overwhelming. I can't go anywhere. Why are there so many? There's no point in doing quests, because you can't go from one town to another without killing enough bandits to increase your rep by taking them out.
On the whole, adventure mode is great. All the features are good; it's just a shame there's nothing to buy in towns apart from food, bone rubbish, and clothes. I've found one weapon shop, and one gem cutter's so far.
The game, as it stands now, would sorely benefit from the ability to feed your followers, equip them with armour and weapons, and a hospital for adventurers.
It's still great though. It reminds me of Syndicate. Kill bandits so that you can persuadatron people.