The USA has needed a massive political shakeup for a very long time now. We have to respect the fact that their ultimate choice at the ballot box was between Hillary Clinton and Trump. All Clinton had to offer was "more of the same" and she carries more adverse baggage than Trump does.
Obama has turned out to have achieved almost nothing in his 8 years as PoTUS and his only significant legacy will be that of being the first black President.
He has also made some very silly comments in the past 6 months or so, such as commenting on and lecturing the UK on its membership of the EU as he did just prior to the Referendum, and lecturing the President-elect on his future conduct as President.
Between Clinton and Trump I'd favour Trump any day.
Anyway time will tell.