Concidering that many (but certainly not all) posters on RPG.net are rpg snobs who regularly remind me of the same people that vote for movies for the Oscars, forgive me if I don't hold their opinions in high regard. But since you brought it up, you fail to mention that every time the "wiff" factor is brought up on rpg.net, its quickly shouted down as being exaggerated. If you're going to bring up an arguement, you may want to include the entire conversations that occur, and not just selectively farm facts that boost your arguement.
Now that said, Dark Heresy is what you make of it, and is more in line with gum shoe style game, and not an over-the-top gonzo style play many players enjoy. Funny how so many people beat on Dark Heresy for not being over-the-top Gonzo and yet readily accept such classic games as Call of Cthuhlu where the issues are much much worse.
The thing is, 40k rpg is classic RPG design. They purposely designed it so that as they built upon the games, adding games and books, they had an excuse for power creep and the new cool toy. One of the things Palladium is always being bashed on is power creep, and yet 40k roleplaying took that concept and wove it into its game design, making you get to pick a game that fits your play style of gaming level and also allows them to make the next cool class without unbalancing the game.
You, and many powergamers, may want to play over the top, kill them all Space Marines, but many other gamers want to play a low level power game more inline with Call of Cthulhu and Adventure. GW and now FFG are working to ensure that all players of 40k rp get to play at the powerlevel they want to, and not just catering to a small, vocal minority of over the top gonzo powergamers.
Sorry if Dark Heresy doesn't fit your gameing style, its to be expected, but just because YOU don't like it, and a small vocal minority doesn't like it, doesn't mean that the other huge majority of people who actually are playing it and making it a huge success don't like it as is.