What do you want to have replace it?
The Libertarian Party. Preferably a bit more "pro-life" on abortion (and the death penalty--life and liberty go together like the left shoe and the right) and pragmatic on the policy details, but basically the current LP would be ideal. I'd accept anything with a majority libertarian bent.
Probably something stupid. I would bet money they use the term "rule of law" too much.
I doubt it will be libertarian. I can't keep myself from holding out enough hope to ultimately be disappointed, yet it's not enough hope to enjoy thinking about the possibilities of a libertarian America.
What makes you think only Democrats and lefties want the Republican Party to fall apart?
We have a party that actually believes in limited government across the board and can make a difference in national policy.
I should remind everyone that more than two major parties is extremely unlikely to last under the current system.
Indeed, Duverger's Law and all that. Which is why we really need electoral reform--we have far more than two ideologies in this country, and the current major parties do a bad job at representing any of them.