Except that the movie is currently not in production. At all. It exists only as a proposal; and proposals DO change. Weaver and Blomkamp have done their best to deliver rhetoric that currently amounts to, well, not much at this point.
Right now, the current proposal has about as may dissenters as it has supporters. Some people want it... others don't. You'll find that it's evenly distributed, depending on people you talk to. Even polls here and elsewhere hover around the 50% mark.
Blomkamp would be best to make a new 'ALIENS' movie with a fresh batch of characters and ditch the whole retcon thing just to bring back Ripley. He'd win people like myself over in an instant.
-Windebieste.