You guys suck. You don't know what Finn's gonna turn out to be.
We didn't even know Luke was related to Leia until the 3rd movie. We didn't find out that Vader was Luke's father until the second movie. And the beat goes on. I'm usually suspicious of the old bait and switch when it comes black characters and marketing, but Star Wars is the one franchise where Finn very well may turn out to be much more important than he seems in the beginning. That's a SW story arc formula.
JJ had no real plan for Finn. No matter how the next couple of films are handled his intro was handled poor. He put Finn in a situation where he's not as essential to the plot.
Everybody knows Finn was there just for the "rope a dope"
This movie he's off doing his own thing, but the real drama is between Rey and Kylo. I think Finn is going to be good in this movie, but hard to believe they'll make him super important.
Episode 9 we get JJ back which can go either way.