The executive isn't supposed to be wielding power unilaterally. What the president does now, with executive orders and signing statements and line-item veto, is massive overreach.

In a properly functioning democracy, the president delegates authority over most everything to trusted advisors (i.e. head of FCC, or DEA, or what have you) who are placed in that position because they have demonstrated both great political/leadership skills, and appropriate knowledge of the area they are governing. The president still has the final say-so in the form of veto power, but that's pretty much it.