What a bunch of crap.
The President is hardly powerless, and a President Trump should be terrifying to any thinking American.
Simply hinting that the United States will not stand by NATO could result in Russian aggression in the Baltics and Central Asia and general destabilization in Europe.
Nominating even worse Supreme Court Justices than Bush could result in further erosion of the civil liberties gained in the last 50 years. If you're unhappy about Citizen's United, just wait for Trump's nominees.
While Hillary has not taken what I consider to be principled stands on many issues, such as approving Dick Cheney's war in Iraq, she is basically leftish middle of the road as far as congress goes. While I would have preferred the option to vote Sanders, the "incompetent warmonger" tag could , by your logic, be applied to most of congress for the past 200 years.