the only way they can redeem themselves is to show us the real red john in season finale, with real one-on-one 30 minutes long like conversation that all fans deserve and where everything will be unveiled. (with no promos, pictures, articles before the episode of course)
but in the episode before the finale, somewhere at the end of it, here's what must happen: patrick discovers a big shiny red john smiley face up on the wall and a dead body (dead body of a character played by bruno heller himself) and he feels dread and knows, knows that the real red john is still out there.
AND, as a bonus, we get to see a flashback of red john mutilating over and over, and laughing while he does it, bruno heller's character.
that would be a good start i think.