I would like to see an episode where transporters are introduced only to have a standard transporter accident that wreaks havoc of some sort on the crew. Then the conclusion of the episode is that this technology is too dangerous for use aboard a starship and it is sent back to the drawing board until it can be perfected.
As long as it's not the series finale: "The Orville: The Motion Picture". That would be a mangled mess...

But, in seriousness, a one-off like that would be interesting and you nailed the plot marvelously.
