In 2012 we had many front runners before we got back to nominating Mitt Romney. This situation is happening again for the 2016 primary and the primary season didn't even start yet. We had a taste of Marco Rubio, he was leading most of the early primary polls with a pretty large lead, but he faded out right after the immigration reform plan collapsed. Once Rubio lost the front runner position Chris Christie, Rand Paul and Ted Cruz pretty much were fighting it out, with one candidate leading the other by a point or two. Once Christie was reelected by a very large margin, it seemed that Christie would emerge as that early primary favorite, which sometimes works out and other times does not. (You can ask George W. Bush about how it feels to be the early favorite and win, and you can ask Rudy Giuliani on how it feels to be the early favorite and lose.) Right when we were about to give Christie the early front runner status the bridge scandal came out. Since then Christie is beginning to fade out. So now the GOP is left with no clear front runner.
According to the latest polls its pretty much a tie depending on the poll between Paul Ryan, Jeb Bush, Rand Paul, Ted Cruz and Mike Huckabee when he is in the polls. Christie is still polling close or a little higher than the names listed above, but I expect his numbers to drop a little more over the next few weeks.
With no clear frontrunner in the race, this gives a big opportunity for sleeper candidates to rise to the occasion. The sleeper candidates could be Ohio Governor John Kasich, Congressman Peter King, New Mexico Governor Susana Martinez (Declined to run for President, but so does most people), and Nevada Governor Brian Sandoval. All these potential candidates have very strong records and a lot of qualifications to be President.
Throughout the whole 2016 Republican primary we are going to probably have a bunch of front runners just like 2o12. The only difference is we wont have an inevitable front runner like Mitt Romney.