Sorry in advance for being "one of those" people who answer someone's question with an answer to a question that the person didn't actually ask...
But have you considered not taking a river cruise? I also had in mind that the only thing to do was to take a cruise, but after a gigantic amount of research we (gf and I) instead booked a private car that took us along the exact route as the cruises, but with our own private guide and at our own pace. And then we stayed in some of the very nice (and very cheap) resort hotels in Aswan and Luxor instead of worrying about the condition of the boat. And then we did a few hours of sailing in Aswan in a felucca to get our Nile sailing checkmark. All for quite a bit cheaper than the Nile cruises and for what I think was a perfect way to see upper Egypt.
Feel free to ignore this if you are really set on a cruise!