Rebooting the first alien film would bring some serious consequences, and most serious of all them imo (apart from the more than probable failure as a movie) would be the total loss of the magic and malevolence shrouding the first iconic creature, the one and only true alien in the series, which actually was Kane reborn as the perfect organism, and of course, a lot more than that.
If the alien series would ever have to face a reboot, It should be only to free the creature from more than 20 years of Cameron-itis and his damned influence over the entire franchise once and for all. Still, If this movie was ever to be done, It should not be a reboot of the first film by any means, and of course the creature to be used in the film could also be different to Giger's alien..., but please, at least be biomechanical, human-like and perverse like the first one, and with the very much missed regeneration skills that the original alien also had (one of the good things about Prometheus was that, but applied to the hammerpede this time).