This means that depending on how fast you and your AI opponents do that research, the games wilderness and the amount of notables (and even resources) differs.
Yepp, I can confirm this from an earlier normal difficulty game of mine, my first serious one after playing and probing around for a bit. And I should say, that I abandoned it.
In that game one of the NPC factions (Kraxis if I remember it correctly) got lucky and had several "Lost Libraries" around their starting location. Of course their tech research went through the roof ... and sadly also mostly into "adventure tech research". Having barely touched this field myself, the world monster NPC level nevertheless was five at around turn 90. So while everybody was just picking up speed or getting steamrolled (the AI factions were rather lagging behind in troop numbers or resistance), the monster had already finished the race.
I had big monsters popping up everywhere in my backyard and in 50% of the cases also in nice stacks that rivaled one of my main armies at the front ... as if a single troll warrior would not have been bad enough so relatively early in the game. So instead of going after the AI factions I had to concentrate on a mindless never ending monster respawn. Not exactly my definition of fun ... or even a strategy game in general. Monsters as a nuisance? OK. Monsters as a bigger threat than the enemy factions? Way beyond not OK.
In the terms of CIVILIZATION: the only thing that kept an AI with medieval units from being outclassed by my riflemen and cannons was a never ending barbarian invasion of tanks and bombers in my backyard.
If that's what I was aiming for I could play a Tower Defence game ... or whatever those flash games are called.
Thus I seriously hope, that the whole monster system gets a big overhaul.
Rabenhoff