I think that is a bit cynical, and not really true
He is more of a liar than just about anyone, ever, in politics.
Just look at how crazily out of the norm he is among other Republicans.
Per Politifact...
Trump is mostly lying or worse 68% of the time.
Pence is mostly lying or worse only 49% of the time.
Paul Ryan is mostly lying or worse only 41% of the time.
Mitch McConnell is mostly lying or worse only 42% of the time.
John McCain is mostly lying or worse only 42% of the time.
Mitt Romney is mostly lying or worse only 42% of the time.
Rand Paul is mostly lying or worse only 34% of the time.
Trump is so far beyond the other guys that it's pretty stunning.
And in terms of douchebag, he is a million times more of a douchebag than Obama or either Bush or Reagan or Carter or any number of people in this world. Come on now. Let's not pretend he isn't just about the biggest douche ever
So yeah... I really disagree with what you are implying there. The amount Trump lies and how big of a douche he is isn't like almost any other President we've had in recent history.
It's okay to just say "Shit, yeah, he is a giant lying douchebag, but I think his policies are good and are helping our nation." I am sure he would be a fun guy to party with, but...