I guess if more Republicans ran as dems by taking all their issues away, they'd win too if they lived in a state like California. It's the demographics, yaknow. :-)
I think it's a brilliant move. Register as a Republican and govern as a liberal.
All but die hard partisans on the left are potential supporters and their clones on the right will support you regardless of what you do. That solid base, from mid left to partisan right, will pay dividends in the center.
The partisan right is a sucker for rhetoric and the mid left will settle for tepid results. Talk right, govern left. Perfect.
It's simply brilliant.