Your right- I got a bit carried away: Its not real outrage, seeing as its only a game. Its more Disappointment, seeing as I payed for the game and I was hoping to get material for the game and support for it. Instead, we haven't even seen an Errata for even the most basic things (shield robes @ 5k Thrones anyone?). Now, this isn't about needing a document to help me fix obvious mistakes like that, but more so about taking the time to back-up the products.
Your also right about not wanting it, not buying it: as a separate line, the product caters to a different clientele. Which is a shame, because as I said, I'd already pre-ordered it and I am very likely to cancel my order because this isn't the product that was promised to me (and likely not at the price that was promised either.)
1- DH is vast enough as to allow for several types of games, not necessarily limited to Inquisitorial Investigation. Agreed, there's limited material on waging war of a long term in the current books (In the Inquisitor's handbook is about the biggest set of information that.) However, Only War could easily have done for the Guard what Book of Judgement (A very good book in my opinion) did to the Adeptus Arbites (Given them a life of their own, outside of the Inquisition). The mechanics are all already there in DH, from cell directives to, as I said, the same likely talents and skills that we've seen across four other lines. Hardly anything that requires its own book.
2- You can already find your low-powered Death-watch in Dark Heresy. Virtually the only thing that's NOT there is the Cohesion mechanic. Again, is that something that will sustain and make viable an entire book?
3- I don't agree: and either way, the Imperial Guard isn't limited to Guardsmen. You can have Sanctioned Psykers [DH], Priests [DH], Medics [Adepts?], Mechanicus troops [Tech-priests, Secutors?]. All those have a place both in lore and in practice in an Imperial Guard themed campaign that wouldn't require a line of its own.
Some alternate ranks would have easily covered the missing points and allowed for more specialization. Not to mention, would have made the games truly compatible.
4- A BC rules updated version in a Pro-imperial light MIGHT be interesting, your quite right- but that doesn't make it compatible. It makes it into a rehash. A double Rehash, actually- a sorta protofusion of Death Watch and Dark Heresy glued together with Black Crusade that updated mechanics but doesn't help those of us who still feel the original line still has a lot to give, and a lot of material to work with (the Calaxis sector is a big place and some official material on it would leave me, the GM, more time to work on the investigation, the story, the campaign- rather then having to build the world from scratch only to find out later that the sector really isn't the way I pictured it and thus crash with established lore.)
5- Your right- that was harsh, I shouldn't have included fan-made stuff into the equation and, while were at it, lets ignore the monsters as well [Even though DH, Death Watch AND rogue trader all have different Orcs and are all officials]. However, you can't deny that a) Talents b) Skills c) Pages worth of the combat system and critical tables, mutations, shock and trauma- are all exactly the same, if only slightly different. Huge amounts of pages devoted to the same "ideas", different enough to prevent the games from being truly compatible- but still using the exact same core mechanic. [Ultimate Irony: Enslavers are in DH's Creature's Anathema. So if we find new stats for them in the new book....]
I am looking forward to seeing the content in the book- how much material is truly different that they decided that they couldn't put it in an addition book that would actually enhance another one of the lines that needs a bit of love instead of having rehashed rules that we've seen before but don't really help fix the core problem.
Now, granted- its a two way street: you can say, use the Only War book to retroactively fix Dark Heresy by applying the rules there. Sure, that might work- but will my player, who has been looking forward to playing a Commissar for months now, get a chance to do that with this book- or are they as compatible as the other lines have been so far? (Which is, in my honest opinion, not a lot.)