I don't think I've read many comments that would suggest anyone would hate to play a game about the Imperial Guard - more that the fluff will be copied and pasted across (again), that the core rules will be pasted across (again) and that in order to play and get into this element of the setting some of us will have had to have bought this game system for a fifth time over. No one is knocking the writers, the effort or the Imperial Guard content, just the business model that at 400 pages per book, the core rule sets now cover 2000 pages over five books.
Saying that this takes the piss out of the buying customers doesn't make anyone a hater of the system or the setting, there's a clear and separate set of issues going on.
Each book is not all part of the same system, instead they are all play alone systems. However, they have similar aspects that can be adjusted to allow them to work together somewhat. If you don't believe me just look at the Psyker sections in the books. Customers that buy every book may be upset that parts of the core rulebook for each setting are the same but that is just part of producing a product that can be bought and played if just once product is purchased. If your Roleplaying Group just wants to play Only War they shouldn't have to buy RT and DH too. However, if they do it may increase their overall enjoyment by adding Voidship Skirmishes and Investigation Endeavors.
In actuality by splitting the books up and adding all the information you need in each book, for individuals that only will buy one book the cost is cheaper. It is not until you buy all of them that it is a lot of money. THOUGH your buying several games so it makes sense to cost a lot. Btw, as expensive as Warhammer Tabletop is I am confused that anyone that is interested in Warhammer is complaining about $50 dollars. In all the truth is they are trying to save money for individuals that are only interested in parts of the Warhammer 40k setting.
I like the Guard, they're tied evenly with the Tau as my favorite army/faction in the Dawn of War games, but what you've posted is the kind of fanboy prattle I'd expect on the Deathwatch Forums, not here. I have (wisely) not purchased every last 40k RPG book that has come out but I can understand the complaints from the people who are saying "Not another damn core book." I don't know if this is FFG or GW's idea but the 40k RPG line seems to be drifting into book bloat territory, which is never a good development. Will I pick it up? Perhaps, though I'm going to wait and see first.
Lol! By no means am I a Space Marines fanboy. Though if calling it as I see it puts me in that group, I just gained some respect for them. To the point as I said above its not another core rulebook for any of the other Fantasy Flight publications. It is a game and system on itself. You, just like many people screaming fowl also say they haven't bought all the books. So if you bought Only War and it was connected to Death Watch you may be pissed to have to buy that book too even though you don't like that type of playing. Wouldn't you and everyone else complaining be please to know that when they buy Only War they can play with it right after purchase? Fantasy Flight would love for you to buy everything they ever produce but they don't expect that. Thus, they make sure the games they sell can be played stand alone.
Now I enjoyed DH but the stuff they made after like RT and now OW are more down my alley of play. I know people that are wet just thinking about Deathwatch but by no means is that my cup of tea. So I may see it from a different point than some of yall are willing to. But I hope if you step back and look at how they are trying to market the RPG Books they have, you will be more understanding and happy with how it is being done. I hope that they do produce more supplement books for the other systems. I think if they did they would have more interest in them. They have done great work with DH putting a lot of extra books in it, but that forces new groups to make substanial investments to make sure they have all able material. Some groups may be happier with a new setting with less books. So I expect even after Only War has 3 or 4 extra supplement material books that Fantasy Flight with already have another or more RPGs coming out.