Some would say that this post is, what, two months overdue? And they'd be right, but I'd rather think of it as "Well, I'm doing two years at a time, so really, I'm 22 months early.
...Okay, the next one will be here before February, I promise.
The couple of years of Uncanny X-Men between #149 and #172 see the book go through some strange comic version of adolescence, or perhaps a mutant metamorphosis - If you compare the first of those issues with the last, it's as if more than just the artist had changed: After a year or so of space epics that took the series away from the glossy soap operatic formula it'd perfected during the Byrne/Austin era, the return to Earth brought changes in focus, storytelling and characterization, and made the book what it still is today, in many ways.
Claremont has often made reference to trying to adapt his writing to suit his artist, and the latter Cockrum era feels like the place where that's most obvious. After a period of trying to do more of the uber-superheroics and mindswap drama that had made the book so popular previously, it must've become clear that Cockrum wasn't enjoying himself - Look at the surprisingly bland pages he produced, and also the number of fill-ins - because, suddenly, the book became a space opera, with the Shi'Ar and the Brood pretty much dominating the book between #153 and #167, with only a four issue breather back on Earth in the middle (Two of which, maybe tellingly, are done by fill-in artists). Cockrum's art seems more alive in the space issues, with more exciting design work and more interesting layouts, but the book feels weirdly un-X-Men-like, nonetheless. Despite the family connections to the Starjammers and Claremont giving it his best Alien rip-off (Between this and the Kitty-In-The-Mansion-Oh-No-A-Monster's-After-Her issue a couple of years earlier, he obviously really liked Ridley Scott's movie. Which, considering Ripley is very much a Claremontian character, makes a lot of sense), the X-Men themselves feel superfluous in their own series for the majority of this time; with little work, the stories could've been reworked as Avengers or, more likely perhaps, Defenders issues (The Shi'Ar issues feel like muddier versions of The New Teen Titans stories about Starfire and her sister, it has to be said, but I'm not sure about the timing on who came first).
Cockrum's gone from the book - off to create The Futurians, according to the lettercol, but probably because he wasn't gelling with the series that he'd helped co-create a second time around - before the Brood storyline finishes, and replacement Paul Smith brought a much lighter, much more open style to proceedings; his early work seems years away from Cockrum's more classic, illustratorly, approach but also Byrne's. It's more graphic, and more empty (Look at his backgrounds, which're often missing or abstract shapes or iconography, which seems to fit particularly well with Tom Orzechowski's lettering - oddly enough, Orzechowski was absent from Cockrum's last couple of issues, with Joe Rosen filling in; the return to Orz's smaller, tighter, cleaner letters in addition to Smith's similarly-clean art in #165 really makes the book look different in its entirety). With Cockrum gone, the in-process Brood storyline wrapped quickly (and detours back into more familiar territory before it ends, with Professor Xavier's Brood implant acting more like a mind-control story than the alien abductor of the Cockrum issues) and we're slammed back into territory introduced in the Byrne issues: Not only teen angst ("Professor Xavier is a jerk!") but bondage imagery (The Morlocks with their collared-and-trussed Angel) and questions of identity (But, instead of "Does power corrupt Jean?" it's "Does leadership corrupt Storm?"). It's exciting, fast-moving stuff, and reads at times like Claremont's been dying to do this kind of stuff for a long time, with the speed and smoothness he brings to the material. It's also - and this is maybe my betraying when I started reading the series, the most "X-Men-y" the book has felt yet; a return to the values of the Byrne era, perhaps, but in a different way, and with a broader scope and, for better or worse, less focused intent (Only the Madelyne Prior subplot really meets any kind of quick resolution, although that'd end up undone before too long; Rogue joining the team, and Storm's uncertainty about who she is, open up threads that will continue for years to come). But even more refining of what'd become the cliched Claremont writing technique was right around the corner, just when it'd look like fresh starts were about to happen.