My main beef with the tenor of this whole thread in general is people do not seem aware of the historical rises and falls in executive power. For example, perhaps they did not call it a "unitary executive" then, but the executive power surely reached its zenith under FDR, with all sorts of behaviors and actions we would regard now with boggled eyes and before which even Trump's more radical actions tend to pale. [Perhaps most applicable to this thread, FDR openly wielded the power of the 'independent' FCC to silence his opposition, to the point where NBC and CBS felt compelled to announce they "would not air any broadcast that was in any way critical of any policy of the Administration.".] Everything worked out OK.
Ironically, of course, that's also the guy who was probably most responsible for the explosion of the size of the administrative state - he really, in a meaningful sense, refounded American government. And while there was good and obvious reasons for the immense expansion of the administrative state, and I'm open to legal reasons either way, I'm becoming increasingly convinced that there's really good social reasons to not have "independent" agencies - I suspect more direct democratic input (the President does X) nets out better in terms of social trust and cohesiveness even when it makes often much dumber decisions.