Ford did the right thing, but he did it in the wrong way. Waiting until a Sunday morning to issue the pardon in a very quiet way just raised people's suspicions of a shady deal. He was right to want to put Watergate and Nixon behind him and get onto the business of governing and moving the country forward. But he didn't really get an apology or explanation from Nixon. And, many others implicated in Watergate didn't get anywhere near the same break.
Justice was not really served. But, nothing good would have come out of making a three-ring circus of putting Nixon on trial, calling witnesses, etc. He might even have looked like a pitiful martyr.
Certainly the pardon hurt Ford's re-election prospects. So did his humiliating appearance before the House Judiciary Committee--he didn't have to appear (executive privilege), but his well-intentioned appearance subjected him to all sorts of unPresidential abuse. It was an early example, of many to come, that showed Americans that Ford wasn't really Presidential material. He lost through an accumulation of bad moves.