I have been to Egypt and so I research this question every couple of weeks.
There are still quite a few European tourists going, and the new government just opened up the stretch of the Nile from Luxor to Cairo, which had been closed for decades since some really bad incidents of violence happened there.
So the "full Nile" is now open from Aswan to Cairo, and if you Google you can find some reports from it, because they invited a lot of European press people.
Most US companies have dropped it completely. One exception is Abercrombie & Kent which does individual package tours (small groups) and also puts together charter groups for bigger river boats.
The company has even called me to try to convince it is perfectly safe to go, but like you, being honest I do not feel I would go right now. I don't want to be a "fear-monger" but look up the reasons they closed the lower Nile in the first place, then research the ongoing demonstrations in Tahrir Sq. and the sacking of the Intercontinental Hotel (near the square) just about two or three months ago.