I can and will agree, that practical effects would be the only why to go for the remake. Using CGI only as a way to enhance the practical effects. (Hiding zippers esc.) But I can also see studio interference on the movie as a whole.
Let's go cheap..... So...... CGI to the rescue!!!!!!
At one time CGI was expensive, but nowadays it's cheaper than practical effects.
....
I'm sad now.
I do hope Landis is able to make this movie a reality.
As for other reasons to remake a classic......
$$$$$$Money,Money,Money$$$$$$$$
Honestly, I have heard worse reasons for remakes. One day, they will remake Jaws.