The point of the hanger battle scene is: 'The two "mothers" fight'; Not 'Look at all this blood we throw at you!'
Bishop isn't being ripped in half because the scene needed someone to "die"; he is being ripped in half specifically so that only Ripley would be left to fight the Queen in order to protect Newt. Him being torn apart has a narrative and thematic purpose. It doesn't just happen for the sake of "gore". That subtle difference is one of the many many reasons why Aliens is far superior to the prequels.