Dear lord, nothing would be more enjoyed by players than staring at a black screen while they are dead. Think about what you're asking for for a second. Does this change at all make the game more fun or does it provide a minor benefit for a major drawback? Yes, traditionally after the joy of dying it's been known to be a great idea to force players to stare at absolutely nothing. Does that not sound ridiculous to you?
People will ghost no matter what you do, if you don't think actual spies exist in this game you're two steps behind the curve.
I think a compromise would be to make it so that players can only spectate one side ever. Keeps death from being mind numbingly boring, yet gives spectators something to watch. Sure people might be able to neutral spec an opposing team, but without the ability to free cam or see where their chosen team is located the efficacy of such tactics is greatly diminished.
