My thoughts. This may take a while.
It's all going to turn on it's head and the Charlie higson did it. The ex husband would be the most obvious suspect from the get go. Plus LH says "she never trusted you" a weird thing to say about someone she was married to, unless in an abusive relationship. Plus he's being spying on her with his laptop that's at her house.
Also Rory the vicar is just there so that everyone can say "I think it's the vicar". Maybe a decline of traditional community subplot. See also local newspaper and scouts (?) from first series.
DT and LH deffo didn't do it, everyone else is v. v. Dodgy.
Mark won't kill joe, he'll get close and then end up in tears.
Something else is going on with the men in broadchurch. At best they're all filianderers at worst wife beaters and rapists.
Possible porn sharing/dogging/rapist ring.
Finally, DT's daughter is the star of the porn on miller's son's phone. It's more than a picture but that's all she felt comfortable telling her dad. Rope guy maybe the man in the porn with her.