Rossi would be easier to beat then Didier.
I would have supported Didier, but I would think Rossi has a better shot in the fall, due to name recognition. He has been close to victory before in state-wide elections and the environment is much better this year than it has been for some time for a GOP candidate. Of course, I say this from a state just about as far away from Washington as you can get, so I do not know the ins and outs of the local scene.
Didier was an uphill battle vs. Rossi, who already has two statewide runs and much more name recognition.
But if you take WA-3, where there were three candidates for the GOP spot and only one for the Dems. And the three GOP candidates together got 51% vs. 31% for the Donks.
I think Palin picked some people who she belived in, more Tea Party than mainline GOP, who obviously needed a boost to have any shot. I think it builds loyalty between the Tea Party types and Palin, which is a lot of benefit to her, regardless of the outcome of the individual races.