Primary elections are important in that each political party gets to choose its main candidate to go against another party in the general election. Primaries are the only way, thus far, to whittle the field to just two candidates. An open primary is an alternative to ones within just one party, as states such as California experiment with a new way to preview the general election.
Yes, primaries in US elections are still the good way for the elections. In my opinion, keeping what we already have would ensure the future because we have experience about it. Abandon the primaries might cause some problems with the elections and should be studied before applying it to real life