The conventional wisdom says that the X-Books went completely off the rails when Chris Claremont left. That any forward momentum in the story department had been sacrificed on the altar of the hot artists of the 90's who, ironically, almost immediately packed up and went to form Image, and proceeded to make lots of money doing terribly little.
The X-Books, meanwhile, in the hands on Fabian Nicieza and Scott Lobdell (mostly) went in a more conservative and workmanlike direction. I've often wondered if the mostly status quo early to middle 90's for the books wasn't a reaction against what happened with the Image boys--perhaps handing over unchallenged power and profit to rising young stars who immediately bolted for greener pastures made them a bit gun-shy about creating new stars that might presumably follow in the Image founder's footsteps, and so Nicieza and Lobdell were seen as safe hands, handed the keys, and warned not to give away the farm or anything and off they went.
Not that this was a creatively flat period for the books--after all this was the time of Age of Apocalypse--but generally one could pick up an X-Book in those days and know what you were getting--able plotting that mostly kept all the big plots ticking over and character who were drawn to look like they were constantly in pain (Andy Kubert on X-Men) and characters who were drawn by whatever fill-in artist they could grab on short notice (Uncanny X-Men) For people who liked that sort of thing, they would find that it was the sort of thing that they liked.
Of course, as Lobdell's tenure was winding down, they were pushing against the grain somewhat. Onslaught was initially an attempt to bring some darker shadings to the previously saintly (more or less) character if Professor X before it was hijacked by Marvel editorial into something entirely else. Operation: Zero Tolerance was, initially and attempt to bring a little bit of jeopardy into the X-Men's world by stripping away some of the accumulated trappings like Shi'ar technology and fancy planes and shake up the team by introducing new characters. It never really came to much, but Lobdell did try to kick things into a new place on the way out the door.
But no one much worried. The replacement writers, Joe Kelly and Steve Seagle, had a tremendous amount of buzz from works elsewhere, and there was a real sense of anticipation to see what they'd do with a franchise that seemed resolved to play it safe whenever possible. Of course, that was more or less nipped in the bud by editorial and replaced with a bizarre, borderline incomprehensible storyline featuring Cerebro gaining sentience (this kind of thing happens a lot with X-Men tech) and creating his own team of X-Men who . . .look, it's really not terribly important. Suffice it to say, from 1998-2000 things will be, at best, a little confused for the books.
It's not all bad, of course, Magneto gets to take over Genosha (having long outlived its purpose as a rather obvious Apartheid metaphor, something had to be done with it) which leads to a great moment where the X-Men have an existential crisis, as having only a mansion to offer as a mutant sanctuary when the opposition has a whole damn country to offer mutants. But by and large, it's mostly just lurching from one thing to another. Paul O'Brien has a certain affection for the ascension of Alan Davis to writer of both titles, but I myself wonder if it wasn't just because things finally seemed to be on some sort of track and it wasn't just spinning wheels anymore.
Anyway, this all leads, more of less to The Shattering, a crossover that leads into another crossover (The Twelve) and is less a coherent story in its own right and a weird bit of sausage--half of it is occupied with the fallout of plotlines before (wherein the X-Men visited a planet full of Skrulls) and the rest turns on stuff that hasn't happened yet (Apocalypse is slowly gathering his forces in the background until about halfway through) Read as a whole, it doesn't make a terrible amount of sense, mostly because it's a deck clearing exercise. It would hardly be remembered at all (none of it's all that neccessary to understand The Twelve, which was a mess all its own, of course) That something like this would be published means almost certainly, other "barely there" crossovers like Dream's End (the 2000 crossover. A little footnote here--"Dream's End" was also the original name for this crossover, but it's now been renamed "The Shattering" because 1) this is all very confusing enough as it is and 2) "The Shattering" was on the cover of the first issue and hey presto, they had a title for this trade after all) and Eve of Destruction should be collected any day now. Lord, think of the poor trees.
Anyways, the Shattering features a lot of running hither and yon and some rather terrible artwork from Adam Kubert, who, it appears, was experimenting with drawing people as crosshatched gelatinous blobs, Alan Davis whose work is very reliably clean and pleasing to the eye, Brandon Peterson, who, it can be said, does the best with what he's got, as really it seems everyone is doing here.
To the extent that this mess can be termed to have anything approaching a coherent plot, it's this--Professor X is acting all paranoid and drilling the X-Men relentlessly, causing discord with the team. There's a guy named Death walking around killing people with a sword. Phoenix and Cyclops (in one of the few good things about this run of issues) begin to see the ship sinking and make arrangements to get off only to be dragged back in, Mikhail Rasputin shows up again for confused reasons (a leitmotif that's synonymous with the character, really) Professor X disbands the X-Men and Death kills Wolverine, who turns out to be a Skrull (the other good thing about this run--like the Thunderbolts thing, this was one of the few times Marvel managed to keep a secret successfully) and another ad hoc X-Team is formed so everyone can get together in time for the Twelve to start.
Ladies and gentlemen, if that sounded confusing, at least you didn't have to read the damn thing. Welcome, well and truly, to the nadir of the X-men as a franchise, wherein the powers that be will be so desperate that that Claremont returning to fix this mess will seem like a blessing (which creates yet another nadir, by the way) and finally, two or so years later, Grant Morrison comes in and makes something interesting happen.
I'm not entirely certain why Marvel collected this, short of to cater to the market share of people like me who enjoy page after page of metaphorical car wrecks and find a peculiar fascination in watching venerable franchises stumble drunkenly down blind alleys like this. It's odd that in a time when the Heroes Return stuff was exhibiting a flowering of creativity that the X-Books sort of imploded like this, but given how much of it can be laid at the feet of editorial mandates, it's surely the end result of too many cooks making . . .well, something that can be published 12 years later and marvelled at as a living example of just how wrong-headed things were back in the day.
In short, while this thick volume is ideal for propping up wobbly tables, I wouldn't recommend reading it, unless you find self-flagellation fun, or you're a comics blogger or some other kind of highly-evolved neurotic.