There are better ways to connote the message of "The overblown ridiculousness of Star Wars as a cultural entity is more a ball n' chain than anything propulsive", and it's not to discard two years worth of hype in one Youtube skit-looking action.
Honestly, even if Rian wanted Luke to toss his saber to the ground as a symbolic manifestation of that early trailer quote ("This is not going to go the way you think!"), have him do so with some anger or motivation.
The way it's shot is clearly meant to subvert what fans and the audience think, but why? Why actively annoy and p*ss off all the people who just wanted another landmark quote in Star Wars history? Again, even if Luke says something that still retains how "done with this" he is, at least it would be something.
The SNL skit mentality that pervades his actual actions is unnecessary, and to some, insulting.