A remake of the movies, Lethal Weapon gets to air pre-Empire, which has worked well for Rosewood, until Empire is out of the picture, then Rosewood crashed. TV remakes of movies have not worked well recently (see: Limitless, Minority Report). It might get sampled well, but probably won't get another go. CANCEL
Since this show will have more non-Empire airings than Rosewood, I predict cancelation.
Lethal Weapon is a spinoff to a movie series. Now, we all know that those do very fell (not really). But there are a few outliers, where a spin-off to a movie series will do OK, and I think this is one. People aren the web seemed excited enough for it, and it has received an alright amount of buzz, trailer views, etc. I do think the show will be renewed.
I don't think this one will do well. It may be a time slot hit when Empire is on, but movie remakes haven't done all that well lately and I don't think this will be an exception, or a stand-alone success. I'm leaning cancel.