Quoting mqpiffle, reply 5Suggestion: Try setting monsters to 'dense' in the startup options and see if you like it.
I already always had monster to dense, but the problem is: you have more monster in the beginning, the suggestion is about monster spawning during the game, not at start.
I think his point is that some people don't like it, and that an option for this is better than something presented after the fact as a given.
Personally, I have no problem with the idea of lair spawns outside the ZOCs, but it would have to be handled very carefully to seem realistic, and not as a means of throwing various ways of sapping resources from the player. If it worked correctly, it would be a nice addition to the game, in my opinion. If done poorly, it would only draw attention away from roleplaying, and to coded conditions.