I would not be opposed to Walker, Cruz, Palin, or even West.
Lukewarm on Rand Paul.
Hell no on Jeb, Christie, Romney.
Think of an effective presidential candidate as someone who can generate support among voters in three key areas:
1. Executive Leadership
2. Political Philosophy
3. Personality
The problem the Republican Party has faced since 2008 -- and it will come up again in 2016 -- is that there is a different potential candidate who grades out best in each of these areas. And none of them are very strong in more than one. My take right now is that the top contender in each of these areas is:
1. Executive Leadership -- Mitt Romney
2. Political Philosophy -- Ted Cruz
3. Personality -- Chris Christie
The challenge for the GOP is to find someone who is very strong in one area, reasonably acceptable in another, and can diminish his/her weaknesses in the third.
I would also point out that the Democrats have a much easier approach to selecting presidential candidates because in every election it seems like they are willing to completely ignore one of these three elements entirely. Barack Obama was nominated because executive leadership capacity has meant nothing to the Democrats in recent years (and it really shows). Bill Clinton was nominated in 1992 even though nobody knew what his politics were (he had as much direction as a fart in the wind).