I think Merc will easily romp it. They've got the performance, and as with last year, a few reliability niggles but nothing like engines blowing up Renault style.
A piston going through the block is slightly more annoying than a couple of brake and electrical gremlins, and really the only time another team wins, even ferrari, are because there's an issue with the car.
It might get better towards the end, but it just looks like Merc simply change the strategy to cover the fezzas and that's it. There's no one else to worry about. Williams race engineers seem to lack any sort of vision or risk taking initiative, which is a shame.