The Republicans have tried the center Right thing twice already and lost. Mc Cain and Romney were considered by almost everyone to be super moderate and not very conservative.
But then everyone has their own idea of what a "real conservative" is and what it actually means to be "far" right.
When people say that, I always ask, what does that mean exactly? It could be something different for different candidates.
Donald Trump isn't philosophically a conservative. But on some issues, like immigration he's obviously very right wing.

But as for this "we need a more center right guy" idea, it's been tried and done many times on every level of government and its been a complete failure. That's why nobody wants Jeb Bush. What's the real difference between Jeb Bush and Hilary Clinton? Not much.
People are sick of the same old politics and establishment politicians especially people who vote on the Right.

You're better off losing an election anyway than winning and getting some moderate guy who breaks every campaign promise and stands for nothing what so ever.