I think that nearly all of our Presidents of the past have ideals and policies that are relevant today. All of our past Presidents had the aim to make America a better place, to bring us into the future as a world power, and to make America the ideal all over the world. Reagan was no different and our desires for America today are no different than our desires 30 years ago.
President Reagan was the politician that advocated a trickle down economics, which every economic professor and historian has proven that it does not work. President Reagan was alive in a specific time where we were at odds with the Soviet Union and "fighting" communism. Different times require different measures of thinking. We may be odds with Russia, but it is close to a free enterprise/democracy. We now fight radical terrorism and not the ideology of different economic and sociological ideals.
The political candidates throughout American history have been largely from elite, blue blood and have been largely chosen behind closed doors. The fact that anybody believes the charade anymore is so entirely laughable. The people who benefit from political decisions own every single candidate who has even a marginal chance of winning in each election cycle. The agenda gets pushed forward regardless of who dances on the stage.
Ronald Reagan's policies, most commonly known as Reaganomics, would no longer hold up in today's political race. Reaganomics was centered around widespread tax cuts, increased military spending, deregulation of domestic markets, and decreased social spending. While those points were relevant at some point, they are no longer relevant in today's world. Modern times would favor increased social spending and very likely favor decreased military spending.