Bone density would be a major issue IIRC. Bones that grew under zero g would break a lot under 1g of gravity in odd places. Lots of stress fractures and other painful slow healing stuff.
But I'm drunk and I read that paper 10 years ago. So YMMV.
http://www.defensenews.com/story/military/tech/2015/04/16/marines-test-missiles-on-v-22-osprey/25824603/
They tested it with a laser guided Hydra 70 as well as the Griffin.
Very good read. Not too technical, and gives a thorough run down of the subject. Other than the limited feedback I gave via PM, I don't have much to add.