The writer, Remender, used to own a comic shop.
He says he was rapt with old the old Chris Claremont stories from the 1990s.
So there is a revisitation to some old X-foes - Spirit King, and the Reavers (I really liked this single issue as the Reavers plot, a story about some very bad cyborgs who nearly kill of the X-men, was something I read many times over in the early 90s) - and allusions to some of the old plots (Nimrod's shell is a trophy - Nimrod being a very very bad future Sentinel), as well as recurring appearances by Deathlok.
But it isn't necessary to be up on it. I think it is helpful in understanding what is happening with Angel and Archangel to know he was once a Horseman of Apocalypse. But other parts of what was either going on in other X-titles at the time of first publication, or had otherwise happened in recent X-continuity - the creation of the island of Utopia as a mutant haven for example, some other crap about a thing called "The World" - I just kind of breezed through all of that.
The story opens with a massive, genuinely confronting shock, which Remender clearly wrote in order to get people hooked onto the title. I read in the interview with the writer at the end of volume 1 of the collected edition that this particular story caused the issue to sell more than any other Marvel title that month.
Fantomex in particular is a very complicated character. Remender really plays that out in one exchange between Wolverine and Fantomex as to why Fantomex does a particularly charitable and honourable thing at great effort to an adversary: Fantomex wants to know that evil isn't hardwired into people's characters, and wants to know that there is hope for himself.
It isn't all sweetness and light, though. Some of the villains are very hardcore. The Skinless Man is a real piece of work as is the Age of Apocalypse Blob.
And Deathlok discovers love!
It is just tremendous.
