Good news for the Left is that the GOP field is full of RINOs who want to be liked. Jeb Bush is another McCain and Romney. Conservatives want a candidate with balls that is going to come back fighting when the Left's attack dog media and other pawns try and smear and shame a conservative candidate. Trump called out an immigration problem where are large number of Mexicans and those crossing the Mexican border are doing so in a manner that breaks US Law and has negative impact and ramifications. He did not say ALL LATINOS are doing this or that ALL LATINOS are causing problems.
GOP Candidates would be wise to fight more like Trump instead of trying to appease like McCain and Romney. The Media is going to smear whomever is the final candidate as a racist, anti-woman's rights, and anti-immigrant no matter what so you damn well better get a sense of fight, fuck off, and not give a shit about the Left's tactics. Milquetoast Republicans are the worst.
I agree that the GOP candidates need to tap into what is angering Americans--that is key to gaining support.
But how they do it and how to address the problems are also. necessary. Trump is throwing out some wild ideas on how to address immigration. However, his ideas have been shown not to be feasible.
You need workable plans, else people are going to point the flaws out and leave you for another candidate.