This thread might get locked. However, until then...
I think DO should remain separate. For all practical purposes, MD and DO is functionally the same thing these days (except for OMM, and MDs are starting to accept and incorporate that into their education, if not their practice). However, I think that it is a good thing to have the two systems operating side by side, separate but (mostly) equal. I think it allows each to innovate, to explore aspects of medicine and medical education that the other does not, and to cover each other's shortcomings.
For example, there was another thread where we were discussing the growth of DO in recent years as a response to the rapidly increasing need for primary care physicians. MD is simply too slow to expand or build new schools, for a variety of reasons; DO was flexible enough to cover that. I think that as one system discovers a weakness in its scope, the other can fill the gap, so to speak.
These two schools may have doctors that work together, but in a way, they're still in competition with each other. And that, my friends, is capitalism. 😀