Everybody should remember that this deal still has to clear a few legal, regulatory hurdles. It is possible that several different government agencies could block this transaction. Considering that the current climate is very uncertain with regard to mergers and acquisitions (AT&T and Time Warner's merger is currently facing a regulatory hurdle), this deal could face some scrutiny.
From my own personal analysis, if the deal goes through, a lot will depend on who stays and who goes in the leadership positions. Stacey Snider, currently heading the film division, has hinted another Alien will go forward. But, rumors are swirling in the trade magazines that she will be leaving her post.
So, we have several different possibilities:
1) Within the next 12-18 months, there is a transition period where many of the same staff will stay in place. The current staff quickly greenlights the next Alien film and it moves into production
2) Snider, Emma Watts, or some remaining deciders stay and move ahead with the next Alien film.
3) Disney puts on the breaks and brings in someone new. This new person will do an evaluation and what happens is anybody's guess.
If they are following their current model, we could see:
a) Star Wars-like soft reboot/sequel with many of the same formulas of the previous entries
b) Indiana Jones-like status - working with the original talent (Spielberg, Marshall, Ford) with a "promise" to make a film but no serious work commitments
c) Or obviously the film gets shelved.
