As the title says there's SPOILERS ahead, so stop reading if you haven't seen the movie.
Now, my theory about Freiza's gold color is that gold sort of represents long-lasting or eternal. Alchemist supposedly could turn normal metals into gold and was sort of the key to eternal life. His gold form could be that same concept. Mind you, I'm not very fond of the color, a new look with the same color scheme would've been fine by me.
Dbz Resurrection F Frieza theory SPOILERS
Now, my theory about Freiza's gold color is that gold sort of represents long-lasting or eternal. Alchemist supposedly could turn normal metals into gold and was sort of the key to eternal life. His gold form could be that same concept. Mind you, I'm not very fond of the color, a new look with the same color scheme would've been fine by me.