This is a very broad question (and one that will change over the next few weeks and months when the administration and congress weigh in), and could be overly subject to opinion.

But: is this new Executive Order really legislation from the Executive branch that is not allowed to legislate? And/or is this "meta-legislation"? And does that matter?

President Trump signed an order Monday aimed at cutting regulations on businesses, saying that agencies should eliminate at least two regulations for each new one.

The White House later released the text of the order, which added that the cost of any new regulation should be offset by eliminating regulations with the same costs to businesses. It excluded regulations regarding the military. Trump wants to scrap two regulations for each new one adopted - The Washington Post

Could Congress reverse it with their own legislation?