The biggest drawback I've seen with DO ortho programs is many of them are based in a consortium of small community hospitals. That may be great for one-on-one supervision with attendings and getting sufficient case numbers, but many of the specialty rotations like peds ER and trauma have to be done at unaffiliated tertiary centers. Most of the MD ortho programs are based at large academic centers and have more rigorous didactics. Also like you said, most DO ortho programs have very little emphasis on research.
That being said, ortho is still a very competitive residency no matter where you go so the odds of producing a well-trained competent orthopod even at a small community hospital program is still high. These are gunners who aren't the types of people to do the minimum work necessary to get boarded.
True, many orthopedic programs are community based and thus why I consider the ACGME merger to be very beneficial in that it requires adding many facets these programs were missing.
I just wanted to clarify though, that the ortho (DO or MD) curriculum doesn't include Peds ER. I get what your saying though. We have two of our subspecialties (onc and peds) at away spots (1.5 hrs away)