My own issue with the President's birth certificate was that the one he had originally released would not have been valid for most lineage societies. I haven't yet seen it, so I won't comment further on it.
The Donald. My own feeling is that he is there to bluster for the GOP, until they can find a viable candidate. Right now, no one candidate stands out - I even got a call from a Newt Gingrich for President committee the other night!