I sort of saw it coming but as the previous poster said, not as a "full reveal".
They've opened up a massive can of worms because she has seen literally everything. Dex's full killing process - the room decked out in plastic sheeting, the victim wrapped up to the table and the knife through the chest. It will be pretty clear to Deb now that Dex was/is the Bay Harbour Butcher.
I'm just worried if they'll be able to tie up everything in 12 episodes without stuff being missed out and/or rushed.
Roll on season 7.