Perhaps the Board of Trustees should be more concerned with the school administrators who actively orchestrated the cover-up that allowed a sexual predator of minors to have unrestricted access to the campus campus facilities to commit his crimes, and spend less time worried about a power struggle against somebody who already announced his intention to step down.
Their actions reek of pandering to the national media, who have been almost universally assailing Paterno over the past couple of days. His firing just seems like a knee-jerk reaction of "we have to do something RIGHT NOW" to present an illusion of "we're dealing with the situation". But the fact that McQueary's status was not addressed last night seems to confirm that they have no clue on how they need to proceed.
Pedophilia, and particularly the heinous nature of Sandusky's cimes, is going to be a very sensitive subject. I get it that even offering the slightest bit of support or "benefit of doubt" to anybody remotely aware of what happened here has the risk of being misinterpreted as an implied condoning of the action itself. But it seems like there is far too much emotion in the discussions I've seen and heard, both on radio/TV, and on social media such as Facebook. I think there's been a rush to judgement on exactly what Paterno was told and what he knew.
For all we know, after Paterno reported to AD Tim Curley what McQueary had told him, he may have been told (after some time) by Curley that "we looked into it, and the story is unfounded", i.e. the official cover-up story. At which point Paterno moved on. McQueary certainly doesn't seem to have further pushed the issue to anybody.