This is the right call - but ultimately since a Manchin run was always somewhat unlikely and now he's ruled it out, WV Dems must now to pick a top-notch candidate. They must hold the governorship at all costs - imagine the shenanigans the state GOP will get involved in if they have everything. Manchin must help to the utmost amount necessary to make this feasible.
There is no top-notch candidate to hold the seat from what I have heard. Though to be fair, Democrats haven't really don't a great job running the state, considering that its quality of life is Alabama and Mississippi levels of bad.
That's because West Virginia Democrats have continued to win by lying to their constituents about coal. WV Dems are no better than all Republicans when it comes to the intellectual integrity of their political rhetoric and policies.