the fact that he will never pardon Snowden tells you all you need to know: this pardon was pandering and suits his own purposes. there are no higher principles here besides quid pro quo.
I wouldn't even call it pandering. He straight-up said the pardon was because the libertarians supported him.
Trump is literally into the second day of his presidency, nobody can know whether he might or might not pardon even Snowden for some reason of his own. I had zero expectation of a pardon for Ulbricht yet here it is and it's more impressive than Obama's pandering (but to me still applause-worthy) pardon of Manning, though none came for Assange.