1. Wealth disparity is an issue because wealth in America correlates very strongly with political power, which wealthy people in turn use to amass even more wealth and political power.
2. Oh man, where to even begin?
a. Repeal of ACA is the most obvious one. According to the recently released report from the nonpartisan Congressional Budget Office[1], 18 million Americans will lose their health insurance in the first year when ACA is repealed. Over ten years, this number will increase to 32 million. In other words, by 2026, one in ten Americans will be without health insurance.
b. Trump wants to strip FCC of consumer protection laws[2]. It's pretty obvious why this will be horrendous for the average American.
c. He proposed pulling out of NATO. This one should also be pretty obvious: NATO is the major force that is keeping Russia in check. Without America there would be a NATO, and without NATO, Russian geopolitical influence would expand massively, reducing America's influence as a result.
d. His cabinet picks are a major disaster. Department of Labor headed by a guy who has fought against labor protection laws all his life. Department of Education headed by a woman who wants to abolish it. Department of Energy headed by a guy who has a degree in animal science. Department of Housing and Urban development headed by a guy whose only "qualification" for the job is having grown up in a poor neighborhood. Environmental Protection Agency headed by a guy who is a close ally of the fossil fuel industry. It gets worse and worse.
[1]https://www.washingtonpost.com/news/powerpost/wp/2017/01/17/...
[2]http://arstechnica.com/tech-policy/2017/01/trump-team-report...