If you're looking for part two, you can find it here.
Easily the biggest problem with Codex: WAAAGH! Ghazghkull's lore is its focus on one individual, Ghazghkull Mag Uruk Thraka himself. Along with furthering the problem of encouraging herohammer tendencies and removing any opportunity for a player to really leave their own mark on an army, the chief issue is that it boils down an entire force to one person. While generals, commanders and leaders are generally the most famous figures in war, they do not make up an entire army in of themselves. They need elite troops, forces at their command, and over time they will be replaced as much as the grunts, meaning that focusing so heavily upon a single figure can limit an army's focus to a single time period.
Now, as discussed before, orks are a potential exception to this. After all, every WAAAGH! is formed out of a mass of boyz following one figure out of respect or sheer cult of personality, with no real history or founding to work off of. However, even in this regard the book falls short due to how it treats Ghazghkull and fails to properly emphasise his role as a legendary figure. It gives the ork plenty of accomplishments, certainly, but at the same time the lore tells them in such a matter-a-fact way that it lacks true impact. Everything is delivered bluntly, is so focused upon Ghazghkull himself with no sense of mystery nor real connection to his foes. What's more is that there was really no sense of immersion.
This isn't a unique problem either, and it comes down to a few things which Games Workshop has been progressively losing over the years when it comes to their storytelling in rulebooks. One of these was specifically brought up in the review of Codex: Farsight Enclaves as it could have single-handedly saved the entire book: Opinionated account. Rather than wrecking the entire Tau Empire and reducing the Aun to a poor, mustache twirling substitute of the Emperor, half of Farsight's knowledge could have been presented as obvious opinion. Entire passages could have been written by Fire Warriors under his command or Farsight himself, accounting for what they had personally seen and give a degree of doubt to their accuracy along with a more personal touch.
The same thing could have been done here to beef up Ghazghkull's legendary status. Rather than bluntly hammering in how awesome Ghazghkull is with direct statements, the supplement could have used accounts from the orks or even descriptions of moments in battles. Prior armybooks in Fantasy in particular used this to great advantage, especially with the likes of the Dwarfs. It added far more flavour than simply telling the reader the information and helped to build up a picture of the kind of forces they were dealing with, making the army stand out more. The original Codex: Necrons, and even some elements of the SPESS TOMB KINGZ, both used this to a degree with other forces viewing the army and building up how they were viewed on the battlefield. This just needed to be directed towards on figure and there were some easy ways to do it.
The foremost among these would be having specific orks be used as viewpoint figures retelling certain events from the conflicts he was in. Some directly, with a few paragraphs or a page of dialogue from them speaking about Ghazghkull like some mythical figure, while the standard text could use a little uncertainty. Opening up a few bits with an almost Conan like introduction would help set the theme of the book and better bring across the idea of Ghazghkull's importance, as would adding a few elements of uncertainty, throwing in legends or tales about him viewed by others. This helps to build up the feeling the book is speaking about some fabled immortal warrior, some legend, rather than just a good commander, as it adds an element of myth to his events. After all, Ghazghkull is supposed to be the chosen of Mork and Gork, so this would fit right in with how he was originally presented.
What's more is that Games Workshop even uses these elements itself in its more successful books. Cypher - Lord of the Fallen (and yes, we will get around to covering it some day) used this to great effect, as did Codex: Legion of the Damned, adding elements of uncertainty and sense of legend behind them through certain impossible tasks. This can only be done so many times of course, but with the chosen warrior of two relatively major Warp entities, Ghazghkull desperately needed this. This wouldn't be any kind of excuse to skimp on details, but it would allow the book to take an approach to really emphasis upon his nature as a barbarian king guided by actual gods.
Even beyond this however, the codex should have focused more upon the enemy and his interactions with them. Now, Ghazghkull is hardly the most complex of characters but there is more than enough for a good writer to use for a good story. He has figures who have followed him since the beginning,to the point of effectively having a loyal cadre of warriors with him since the beginning, an arch foe and even a sidekick. No, really, look up Makari at some point, a gretchin who used to serve as the ork's bana wava and had the Second Edition's equivalent of a 2+ invulnerable save. This was enough for any starter element and make the Wars for Armageddon all the more interesting and find ways to show Ghazghkull in the sort of light the codex really needs. Even if it were just to focus upon Ghazghkull fighting Yarrick alone, that might have actually been enough here. Previous reviews have criticised rivalries having a sort of tunnel vision but, given how well established their particular one is, spending sections of the book developing this would only offer what fans would want.
With the codex skimming over all of that, it really left little to Ghazghkull's actual character. Really the only thing he had going for him was a love of war and the occasional painful messages from Gork and Mork to keep him going. That might have been enough for a side character, but an entire book? There needs to be more elements of substance or to have Ghazghkull play somewhat more of a background role in the book's stories.
Now, this is just the problems we have with presenting Ghazghkull himself. There's still the issue that this entire supplement codex, a book supposed to cover an entire army, is stuck focusing upon Ghazghkull himself. The sad thing though is that the approach it was going for could have worked just as well when it came down to the horde if it had just taken a slightly different approach. Just for starters, the book could feature Ghazghkull's influence by passing on a mentality or the orks following his approach in war.
As mentioned previously, many of the more successful orks by the end of M41 were repeatedly depicted as having grown in power and adapted well to Imperial tactics. They were not those they had fought during the Horus Heresy, nor even a few thousand years ago, now they were a vastly greater threat than ever before. Ghazghkull's ingenuity and his ability to completely alter the battlefield with his tactics was brought up as something exclusive to him, a definite mistake, so why not correct that.
Have the ork warbands following the Warboss not be micromanaged by Ghazghkull or so utterly reliant upon his leadership, but instead be inspired by him. Have them shaped by his ways of war or the teachings of those who followed him (the small number of Warbosses he left to command the WAAAGH! as his lieutenants) but then build upon it themselves. Have them take his ideas, then put a new spin on them and the army itself by having them embrace his teachings but not be utterly reliant upon his presence to remain combat effective.
We have seen this in plenty of other armies and it's worked just as well, the Codex Astartes and the primarchs being the most obvious examples. Guilliman, Dorn and Khan no longer lead their scions but that did not mean the astartes instantly abandoned their teachings the moment they left. Nor were they utterly limited to them, with some abandoning certain aspects of the Codex and other chapters diverging entirely from their parent chapter to follow their own path. The same thing could easily be done here, with ork warbands being influenced by his ideas and developing because of them. Some doing far more to learn from their past foes, others attempting far more unexpected tactics, perhaps even mimicking Imperial tactics like those from Rynn's World and the Blood Axes do.
This move would still make Ghazghkull's influence clear, his genius and power evident to any readers, but it make the book actually about an army. More importantly, it would also offer players far more of a chance to put their own spin on things, perhaps working with certain ideas or established structures. This was actually present to a point (namely the various divisions and units it presented a-la Codex: Black Legion) but whereas that felt added on rather than truly integrated, this would be an opportunity to fully integrate the idea into the codex.
This is really what the book needed more than anything else, to just take what it had, go further, and push to integrate more ideas from past works. With them, at the very least this might have offered some truly great lore rather than something unremarkable at best.