
It's weird to think about the butterfly effect this character unintentionally caused
For anyone who doesn't remember, this is Deb's therapist, the one who made Deb realize she was in love with Dexter—or whatever that was supposed to be. That led Deb to confess her feelings to Dexter just as he killed Travis, causing him to drop the blood slide, which LaGuerta later found. That not only led to Deb keeping a close eye on Dexter, putting her at odds with Hannah, but it also caused LaGuerta to investigate Dexter, which ultimately resulted in Deb killing LaGuerta.
Season 8 might not have changed that much, but there are still a few things to consider. Deb wouldn't have been going through an emotional breakdown or left the police force. If Deb had never tried to arrest Hannah, then Hannah never would have tried to kill Deb. Dexter wouldn't have needed to frame Hannah, meaning he wouldn't have had to run away with her either. As a result the U.S. Marshal wouldn't have been following Deb to track Hannah down and therefore wouldn't have released Oliver Saxon. Even if Saxon had still been released, if Deb had never learned that Dexter was a serial killer, Dexter wouldn't have called her to help capture Saxon. And if Dexter hadn't been planning to run away with Hannah, he might never have had the realization that he shouldn't kill Saxon.
In that scenario, Deb wouldn't have been shot, Dexter wouldn't have abandoned Hannah and Harrison, and he never would have faked his own death. That means no New Blood and no Resurrection. It would have been a much better outcome for Dexter, but a much worse one for everyone else because of all the killers Dexter would never have gone on to stop