And by that point, John Edwards was right out.
As I recall, Gore was viewed as a young progressive, whereas Bill Clinton was largely regarded as a more center-line pragmatist. It was thought that having two young guns who represented two distinct ideological wings of the party (but far from radical), was the right approach, and all signs are that it worked. There was a clear distinction between Clinton/Gore and Bush/Quayle. The feeling was Bill could energize the labor democrats that the Dems had lost, while Gore had some street cred as a liberal that would keep constituencies that voted for Dukakis and Mondale.