RS is numero uno in regards to who should exit first. Those of you who think O'Brien has payed a major role in the draft and FA moves, then he should be packing his bags along with RS. Me, I don't think he had much to do in the way of the draft and certainly didn't get a say in the Osweiler fiasco...but in regards to his coaching, it's been subpar and fort hose reasons alone, I'd let him go since he's had 4 seasons to get better.
I think O'Brien's biggest fault was his desire to keep his hands on the offense. Godfrey was a puppet, not a challenger. He wound up paying the ultimate price...losing his job, while pretty much every fan knew O'Brien was the one really running the offense. So the team fires Godfrey and O'Brien decided it was in his and the teams best interest that he be the HC and OC. This obviously hasn't worked. I think RS just sat back and thought, if I give him enough rope, he'll hang himself for sure. O'Brien should've went OC hunting and found someone who he could click with and share enough ideas to create a revamped offense that allowed the OC to do his job and O'Brien to focus on being a better HC. Since he did none of these things and he's almost completed year 4, it's really time for to go and find a OC job before trying his hand at HC.
RS goes simply b/c of his record, inability to identify talent, and not being in a position to build a winner when he's had multiple RD1-1 picks and drafts with better than 7 picks. This current teams look can be thrown right over to the maestro himself, RS. Tired of his excuses...even though he rarely offers one or takes blame for the current state of the Texans.
As for O'Brien's success with Watson at the helm. O'Brien can thank Watson for making him look competent as an OC. Watson took many broken plays and made something out of nothing. With this OL, Watson converted O'Brien's playbook and converted it to one more commonly known as the Sandlot Playbook. His ability to sustain a play with his legs bought his receivers the time to break routes/coverage and become successful.
It really is time to clean house. Start with a GM who could come in and make lemonade out of the lemons that is the Texans 2018 NFL Draft. Find a new coaching staff that can set the table for 2019 by making a much more competitve team for 2018.