I do agree that the removal of the extinction of animals theme, the removal of Deckard's wife, and to some extent the removal of mercerism detracts from the movie (or at least with the second two significantly alters bits), however not sure if the removal of the "it's difficult to kill someone when you've had sex with their double"-theme is really detrimental.

the whole fake police precinct full of androids thing was probably also better removed from a cinematic standpoint.

on edit: at any rate we should probably take into account that Phil Dick seemed to appreciate the movie https://screencrush.com/philip-k-dick-blade-runner/