I've seen it quite a few times now. People saying the forsaken are the least proper race for monks. Why is that?
Because most people can't think outside the box.
The pandaren monks are known for harnessing their chi to bring balance to themselves and to the world around them, and the forsaken will learn martial arts from them.
But that doesn't mean the forsaken will have the same ideals as the pandaren.
What if their general intention (excluding particular cases) is to disrupt balance instead of bringing it? If you can manipulate chi to keep things balanced, than you can do it to unbalance it all.
The forsaken did the same with the Church of the Holy Light. They got the original, general idea, twisted it in favor of the shadow, added some divine humanism into it and behold: they made a new religion, the Cult of the Forgotten Shadow!
Here are the possible niches they may occupy from MoP on:
- Monks who desire to harness the dark chi and use it as a destructive weapon.
- Monks who wish to train themselves so as to defeat their mind control weakness (natural to all of the undead).
- Jiangshi-like monks who use val'kyr-blessed seals of chi to raise other forsaken without needing to bring val'kyr to the battlefront. (jiangshi are a type of hopping undead from chinese folklore)
so, down with the "forsaken monks don't fit"!