From what I read somewhere some time ago, it was bad enough for them to rework the Movie when it was later released in Europe and here, to include the narration at the end to say that he would return.
Or maybe it was an overreaction to both TFs & GIJoe movies killing off their lead heroes... and getting a lot of bad press over it.
There was even a claim that a kid was going to kill himself or refused to eat (or something) over the death of his hero Optimus Prime.
There's probably some articles online with a google search about the controversy (or on tfwiki.net).