One of the many things that is very concerning is that Trump is doing things directly without a law being created by Congress. That basically gives us a dictator, which is not what the Founding Fathers envisioned.
To be fair, a lot of this is past Congress's fault. They literally delegated rule-making authority to regulatory agencies, which are run and overseen by the Executive branch. Trump, who manages these regulatory agencies, is basically taking advantage of this fact. All the President has to do is remove the people he does not like, and replace them with people who do what he says. They, then, rewrite the regulations.
This is the reason why Congress is supposed to make regulations, not bureaucrats that can be influenced by the President or by corporate interests who infiltrate the regulatory agency.
Congress can take their power back... but will they? Or will both parties use this to install their own dictators?
Edit: Reposted so people can comment.