Flake is at 18% aporoval right now. If he switches parties that will go lower. Republicans will despise him. Democrats, otoh, like ‘maverick,’ Republicans who stab their own party in the back. When it comes to Democrats per se, they while always prefer the real deal to some hack party-jumper—one whose usefulness as a maverick just went up in smoke.
As Arlen Specter found out.