But, there's also no reason to necessarily go with another moderate, as we already have one. Generally, they will pick someone who is a juxtaposition of the candidate. Picking another moderate Democrat (especially an old one) doesn't make much sense. In the end, picking a woman is the most likely scenario, and ideally one that will shore up the weaknesses that Biden brings... which is with young voters. If moderates think that Biden is to the left, then they are not moderates... and were never going to vote for Biden, anyways. Trying to pander to them is a waste of time.
And yes, it was that way two decades ago, the Bush/Gore election was pretty brutal.
It has already been pointed out that you are a Trump supporter. is there anyone Biden could put on his ticket who would get you to support him, instead? Who would that be?