My understanding is that the Snakes aren't really looking at Johnson as an acquistion to help them win ballgames, although he may do that. They're looking at him as the team marquee draw, as in the snowbirds in Aree-zon-ah aren't smart enough to follow baseball for the value of a young team that will muddle their way through a season.
They need a marquee player to keep the masses coming to the ballpark. Are they wrong about their own fanbase? I dunno, I have a feeling that they're not. So they need RJ for the marketability moreso than the pitchability as it were.
Anything above marketability is gravy. So I don't blame them for dealing with the Evil Empire in that case. One, however, wonders why the Padres are interested in making a deal. They've already gone the route of picking up castoff Boomer Wells from the northeast, why Johnson? Are they kidding themselves?