Disney is going to think of Star Wars
in the same way Paramount thinks of Star Trek
: as a property that has famous names that need to be front & center of everything, because the famous names are
the value of the franchise.
Just as Star Trek
was revived with Kirk-Spock-Enterprise, Star Wars
will be revived with Luke-Leia-Han. And they must be young and pretty, so recasting is mandatory.
Imagine the publicity value of recasting Han Solo. That alone is worth immense amounts of PR and therefore money. Of course, there's the risk of them blowing it utterly, and they have three chances to blow it with three iconic characters who we all have strong opinioms about.
But movies are a global business and most of the world barely remembers or cares about Han, other than that he's a famous name associated with surefire entertainment at the movies. Lucas might have ignored all these things when he was one guy in charge of the whle shebang and nobody could contradict him, even when he was creating an unmitigated disaster, but a corporation that answers to shareholders will be far more bloodlessly calculating about it all.