There's a mod suggestion thread in the general FTB chat forum that you can use to express your love for this mod.
That said, personally? I'm not a fan. I've played with Mo' Creatures twice before, and both times it completely broke the game because I was not able to find specific resources anymore. All the spawnpoints for vanilla creatures tend to be clogged up with the mod's new creatures, and a large number of these creatures are predators that kill every other non-predator creature (and sometimes each other too). Want to play with Mystcraft? You're going to need ink. Unfortunately squids rarely ever spawn anymore, and what few do spawn get instantly eaten by sharks the very second the chunk gets loaded (which usually means minutes before you actually get there). And there's no other source for ink. Welp, guess Mystcraft isn't going to be used...
There is an ingame config for spawn probabilities, but after extensive testing, you pretty much need to disable 90% of all added creatures to have even a remote chance of finding a vanilla creature when you need it. At that point, you may as well uninstall the mod, which is what I did.
Not to mention the Ogres. Are you a server admin who hates Endermen, because they completely wreck the landscape if the server runs 24/7 for long enough? One Ogre does in a single Minecraft night what 20 Endermen need a day of RL time to do. Enjoy your wasteland.
