I could be tempted to agree, if the president was chosen by popular vote. The president isn't. And the only positions in the executive that are elected are the president and vice president. On the other hand, the entire legislative branch is elected by popular vote and is responsible to the public every two years for the house and six for the senate (not four). There is a reason the framers gave the legislative the most power, then the executive, and then finally the completely un-elected judiciary.
As to the rest of your post, I will just say that it is only the democrat party that strictly adheres to the seniority rule to committee assignments. Republicans in the Senate use a hybrid system, and Republicans in the house don't use it at all.