Ahhh... but you've just stumbled upon the constant struggle between the the senate and the "executives" throughout history. Regardless of whether the executive was an emperor, king, president, etc.
The senate always "knows exactly how things should be done". Always griping that the nation would be better off if the executive had less power. These legislators conjure up grand laws and hand them off to the executives who then have the task of actually implementing these perfect laws. Most times these perfect laws are horribly unrealistic or inadequate, but the executives have to make them work. This generally requires less desirable decisions to be made.
Then in the US, these same legislators run against the executives and use the less desirable decisions as ammunition against them.
In my opinion, any candidate who even wants to be considered for the presidency must have some type of executive experience. Thats all we need, both the legislative branch and the executive branch getting filled by a bunch of hard core legislators. Laws being passed left and right without anything ever getting done.