With it's first 2 movies, and to some but lesser extent the 3rd, the Alien franchise has already achieved almost perfect execution of it's premise. If it must continue I think the money would be better spent on simply telling more stories in the established universe and trying not to make the same mistakes that the franchise fell into in later years.
I'm sure that the right kind of visionary could bring a new flavour to the idea, and the right team of director, producer, designers and effects people could possibly rival the work of Scott, Giger and Cameron. But history tells us that it almost certainly won't happen like that and that we will more likely get a derivative remake that fails to live up to it's predecessors, and with such a breathtakingly well realised concept already out there, why bother.
That said, i'm never against good movies being made, regardless of whether they are remakes or reboots or whatever. I'm just not holding my breath.