I am playing the Big Dig mod pack using the Technic Platform. Up until about a day ago, my world was pretty normal - creepers, slimes, etc. However, now it seems that I don't have any hostile mobs spawning.
I think it might have to do with when I fell through the bottom of the world after going too deep into multiple Dimensional Doors...when I came out, I was 20+ kilometers from home in the middle of the ocean, where I found a huge dungeon full of spawners. I raided the dungeon for awhile and then spent a long time trekking back to my base.
Are there any "quick fixes" I should try to see if I can get mobs to start spawning again? Could it be the "Mob Extinction" issue? What should I do?
EDITED TO ADD: I think I have at least a partial confirmation that the issue has to do with spawn limits, etc. I traveled to the Nether last night for some Nether stuff, and there were Ghasts a-plenty, along with Zombie Pigmen and Blazes. Also, monster spawners still work in the Overworld - it just seems that there's no random spawns.