“The legislation creating the DNI position stated that the person filling it should have intelligence experience.”
It depends on what intelligence experience means. I held a TS clearance on a black project. We received regular “courtesy” briefings. (My God, where they eye opening!) Actually, I think the public should have received similar updates so the public would understand just what was going on. There was a war in progress at the time, only involving spying instead of guns. Does that count for “intelligence experience?” It is likely Collins has more under his belt than we know.
If Trump's intent is to direct a huge middle finger to all the intelligence agencies then the better way to do that is to either do away with the DNI post entirely or else leave it empty.