I don't know I'm torn on the whole systems.
I mean point buy is cleaner and more efficent leaving more control of your character in your hands, but also allowing more room for players to exploit the system. It also tends to make very static characters without the fluctuations that you see in a random roll, and sometimes those fluctuations are what make a character so colorful.
At the same time, random gen can lead to super characters, or super-bad characters just on the whims of Lady Luck and dice rolls. You also can't always create the character you want, even if the character isn't designed to be over the top gonzo. Sometimes the dice just don't cooperate with it.
Then there is the concept of point-buy and random rolls combined, which can be interesting, but usually they turn out to be clunky systems that barely fix the issues with the other two.
And multiple systems in the same game just lead to confusion and bulky rules systems.
While I have to agree that the character attribute creation system in Dark Heresy is far from perfect, I would say we just keep it now for all the core rulebooks.
Then when you create the obligitory "optional rules handbook" you can put optional rules in there for things like point buy characteristics.