Bruno Heller said that it was very important for Partridge to die in the first episode, but i haven't find out a good explanation of this yet. OK so I will try to explain it.

Killing Partridge (everyone's favorite until season 6) at the first episode before giving away more clues about Red John and not clearly allowing us to see his death ensured that none can be 100% sure about who Red John is. Every theory about Partridge has a big question: "But. what if Partridge is really dead?" and every theory about every other suspect has another big question: "What if Partridge is not really dead?".
By doing this Bruno really ensured that none will be 100% sure about Red John before his actual reveal and he really succeeded. With the blurry death of Brett Partridge everyone asks himself either one of the 2 questions above after completing his thought about a suspect, none is sure.
That's why I tend to believe that Partridge is really dead and the reason above is why Bruno didn't really clearly show us that he is dead, but that's my opinion.