I’m super fucking stoked by Finn’s appearances in the trailer. Maybe it’s my theory goggles that Finn is going to start a Stormtrooper uprising, but it seems to me Poe’s line that “We have a spark that will light the fire that will burn the First Order down” is a direct reference to Finn and the possible Stormtrooper rebellion. What’s more, Finn shows up directly after that line, surrounded by, hmmmm, FIRE as he duels Phasma.
Poe seems to be speaking with repressed anger or sorrow (my God Oscar
Isaac’s delivery help me Obi Juan whoever the fuck you are), indicating
that this was spoken in a moment of conflict whether within himself or
someone else.
Could Poe’s clashes with Leia have to do with how to respond to the possible uprising? Did Finn convince Poe into letting himself and Rose to go on a rogue mission and into possible death, a choice Poe is himself conflicted about? Is that why Leia slaps him, when she finds out what he’s done?
Finn, by the way, is not carrying a lightsaber but some kind of energy pike weapon that seems to work similarly to the energy baton–called a tonfa–that FN-2199 used against him in the battle on Takodana. It not only looks freaking badass, it has a great reach, versatility and can stand up to lightsabers, too. (Thanks @secondtolastjedi for the correction!) This wouldn’t be the first time we saw Finn take a weapon off a Stormtrooper, and I love love love the symbolism here of Finn using the weapons of the First Order against it.

Also the all-black ensemble with a glowy energy weapon…. is anyone going to comment on the similarities with Luke in ROTJ? As I said in my reply to @diversehighfantasy, I see parallels with Luke in my TLJ speculation for Finn, too, particularly my wildly speculative ending.

Furthermore, when Snoke starts saying “Fulfill your destiny” the first shot is directly on Finn, although I think the line itself is said to Rey or Kylo. Is this a sideways reference to Finn’s liberating Stormtroopers being his destiny?