To be honest, I'm not entirely sure how to review 'The Masters of Luxor'. I mean, this is basically a discussion of a historical curiosity, a first draft of a script that wasn't deemed good enough to warrant a second draft, made for a production whose style of drama is now sitting comfortably at fifty-one years out of date. Is it even worth it to discuss the quality here? Does it even make sense to try?
In case the answer is "yes", I can say that 'The Masters of Luxor' as published isn't very good. There's a lot of random conjecture that turns out to be absolutely right for no reason beyond the writer having no real mechanism to deliver exposition about the dead, silent city and its robotic inhabitants. There's not much action over the six episodes, there's a lot of discussion about religion that seems weird and out of place as well as slow and talky, and the Perfect One is simply not very exciting as an adversary. There's some nice atmosphere at points, but it's really nothing that the city in 'The Daleks' didn't do better. Oh, and although the dialogue would certainly have been rewritten further in later drafts (and was rewritten for the script book already, according to the afterword) it still sounds clunky and not particularly like any of the regulars. Basically, it's not hard to see how they went a different direction after this.
But again, the quality isn't necessarily what we look at with this one. It's interesting to read it not because it's good, but because it demonstrates the thought processes of the people working on the series at the time. They knew they wanted to contrast the first "science fiction" episode of the series with the "historical" they'd already done, and their mental focus was obviously on the potential for sterility and inhumanity inherent in science. The unseen Masters of Luxor had gone down a path of eugenics, which wasn't (yet) a component of the Daleks' evil, but both of them shared the notion of a world where science gone mad had led to a world on the brink of death, and a city that was a scientific paradise with nobody left to live in it.
The discarded humanity is personified in both stories; in 'The Daleks', it's the Thals who skulk outside of the abandoned city, scarred by memories of a century-old war. In 'The Masters of Luxor', it's Tabon, who abandoned himself to exile and suspended animation rather than face the consequences of his experimentation. The Thals, of course, are just as responsible for the Daleks (in the original story, at least) as Tabon was for the Perfect One, but their ancestors' aggression and violence is downplayed to the point where the act of resuming the war against their old enemies is seen as a positive act and not a resumption of a campaign of genocide. Perhaps the production team weren't quite ready for Tabon's guilt, or perhaps they simply wanted more sympathetic characters? It's hard to sympathize with anyone outside of the regular cast in 'The Masters of Luxor', and Tabon's self-sacrifice seems more to be his just desserts than a tragic comeuppance.
Or honestly, it could have just been practical concerns. There are a lot of freaking robot costumes in this one, far more than the number of Daleks that appear on-screen. The TARDIS flies, something it did rarely in the Classic Series, and of course the story ends with the entire city exploding. It might very well have been judged unworkable in light of their budgetary concerns. (At the very least, 'The Daleks' stretched out the sets and costumes over an extra episode.)
Ultimately, we may never know exactly what caused this script to be rejected in favor of Nation's story, but I think we can answer one question. In the introduction, John McElroy asks, "In a universe of infinite possibilities, there are of course worlds in which [Masters] was the second story--I wonder if Doctor Who is still running there?" Based on this script, I'm guessing not.