Yes - if you only count the first choice votes, it's no better than a regular election. But in RCV, if your first choice doesn't win, your vote goes to your second choice, or third, on down the list. Ultimately, no candidate can win unless they get a majority of the votes. When it comes down to that lest two standing, the winner will be the candidate that the majority of voters preferred.
If some voters don't rank other candidates, the system is less effective at diminishing the spoiler effect, but unless no one ranks at all, it's never as bad as our current system. In that worst case scenario, where every single voter is as stupid as Sarah Palin and refuses to rank other candidates, the election goes down exactly as it would under plurality voting. It can only be better when it comes to getting rid of lesser-of-two-evils.