Yeah, Mo' Creatures is a blast at first because you're like wow, look at all these awesome creatures, but quickly becomes annoying. Not only is your base CONSTANTLY surrounded/roof crowded with scorpions and wolves and rats oh my, but they make the most ungodly fucking noise ever. I have to go out once every few days just to kill all the shit on my roof because I can't fucking take the noise. And yeah, you pretty much have to turn off ogres or you'll punch your monitor the first time one ends up on your roof or against an outside wall and AE's and destroys all of your machines, wiring, pipes, solar panels, etc.
I haven't played it in several iterations, but I had posted awhile ago that ostriches were broken as fuck too. They might have changed, but previously as long as you got a male and a female "tamed" and put them in a room together, and then put some water or other mechanism to push their eggs out into a separate room, every 10 minutes or so you'd go in and slaughter the new ostriches for drumsticks, cook them up, and have endless food. And once again, they made so much fucking noise that if you didn't put them somewhere a decent distance horizontally away, they'd drive you fucking nuts too. I always intended to set up an automated system for killing them, but they were so fucking annoying that I relished going in there and beating them down.
Werewolves were annoying as fuck because the only weapon that worked well against them was a gold sword, and who the fuck wants to carry that around all the time? So it would take like 30 hits from an iron sword to kill one.
It's a great concept, but exactly as Cam said, WAY too much once you realize that it is more of a nuisance after the wow factor wears off.