Yes the lines get long in the tent if they are not there early. But my experience over many years there contradicts everything else you said. Like you said, they list exactly who will be in the tent every day, and ahead of time. It isn't a 3rd string surprise showing up. There is a set time the players will be there, I don't remember what it is, but it is more than 15 minutes. And I have never seen one player leave early. My kids loved it for years, but they are too old to get in now. Unless things changed dramatically for the worse last year, my experience was very different from yours.
My favorite memory is when my youngest boy came running out of the tent all excited because one of the players signing, I believe it was Spiller, gave my son one of the bottles of gatorade they have for the players to drink. He thought that was the greatest thing in the world!