Remember, Jones v. Clinton was a civil matter, not a criminal investigation. Defendants in criminal trials have a constitutional right to examine witnesses. The fact that the judge is so dismissive with respect to Obama's relevance is particularly troubling in light of the fact that he was interviewed (according to press reports) by the FBI and USA for at least TWO HOURS on the subject.
If nothing else, you would think that in the interest of due process, a subpoena for deposition would have been granted. I'll wager that there will be an interlocutory appeal, and this isn't yet over.
I would add, that information and witness testimony presented during the State’s case, may be tested and impeached during cross, or during the presentment of the defense case. IOW, whatever the outcome of the appeal, Blago’s lawyers will have an opportunity to establish a foundation for calling Obama.