I've been as guilty as any of spending a lot more time attacking Donald Trump than supporting Hillary Clinton. In part that's because there are aspects to Clinton I've not been happy with, and in part because, frankly, there are very few folk the Dems could have put up who I wouldn't vote for rather than Trump.
But that said, there are a lot of reasons for me to vote for Hillary Clinton beyond just keeping Trump out of the White House. This article lists up a bunch of them.
I'd also commend this opinion piece in the Guardian which is less listy, more paragraphy, but makes a lot of the same points: https://goo.gl/CMDqXO
The progressive case for Hillary Clinton is pretty overwhelming