I'm not entirely sure that's true. It served a purpose (moving Rey's force prowess along) beyond "oh look, this bad guy's dangerous so he's going to kill the token black guy." Finn is definitely not a token black guy - he's one of the new faces of the franchise. Plus, it made sense in context: Finn isn't a Jedi, he's just a guy with a lightsaber. No way he's going to win. Plus, he actually put up a fight, rather than being summarily taken out.
Speaking of Rey's force prowess, she got the hang of things pretty darn quickly. Almost too quickly, IMO.
Finn is an awesome character. Cannot wait to see where his story goes from here.
Likewise with Rey. That girl is definitely a Skywalker. No two ways about it. There's a reason we were introduced to her on a desert planet where she was left, abandoned, to be raised by an unsympathetic shop owner... think about it.
And those that say this story was too derivative or just a re-hash of the original trilogy are really missing the major point and tons of subtleties, besides. Yeah, they could have done a massive info-dump and told us everything that happened over the "missing" 30 years... or they could dole it out in subsequent movies and off-shoots making it a more enjoyable, potent, part of the ongoing story.
Here's what I brought away from the film, as it was. After the Rebels defeated the emperor in ROTJ, that left a vacuum atop the Empire's power structure. There was a scramble among the surviving top dogs to fill said void, while the ruling power of the Empire crumbled, allowing the New Republic to seize the reigns for the galaxy. However, the true die-hard fanatics of the Empire all retreated back to the outer-rim worlds and restructured the organization, which became the First Order. The New Republic sent their best and brightest out to set up the Resistance among the outer rim worlds to fight back against the First Order before they can gain enough of a foothold to re-seize the reigns of power throughout the galaxy.
So, during the missing 30 years, the Republic re-established it's rule and reconstituted the Galactic Council (hopefully, without Jar Jar holding a seat), and the remnants of the Empire retreated to lick it's wounds and reorganize into the First Order. The analog here is Germany after WWI, and how the fanatics seized power and founded the Nazi regime. I mean, they all but *told* you that in the movie in several places. It's not the filmmaker's fault if you don't know your 20th century European history. Ha Ha!
Anyway, meanwhile Luke sets about trying to re-establish the Jedi order, but fails, since that's what Mark Hammill always does. And his star pupil becomes Darth Vader happy happy fan boy #1. Probably also has something to do with his father Han constantly referring to him as "Princess" while growing up too... And possibly something to do with Han liking Chewbacca more than him, too. Oh, and I bet the following conversation took place, and had a part in it too...
"Hey, Ben, now that you're 16 and can get your starship license, I need to make a confession."
"What's that dad?"
"Well, you know that ship I promised you could have when you were old enough?"
"Yeah, the Mellineum Falcon... Yeah..."
"Um... well... um... I lost it."
"Whaddya mean you lost it?"
"Aw, you know how it is, son, one too many correllian ale's, and the next thing you know you wake up on Laos Vagus IV with a shaved Wookie and a strange new face tattoo and can't remember anything... but that's another movie..."
"Awwwwwww Daaaaaaaad...."
So, the reason made what is essentially yet another Death Star? I imagine it has to do with only having 30 years and already having the plans for that big gun just laying around in the Imperial ruins. Besides, it always worked out so well in the past... um... hold on...
And, one last point in this oddball stream of consciousness idiocy, Han *had* to be the sacrificial mentor in this film. The first film in both other Star Wars trilogies had a sacrificial mentor figure who took pointed the "hero" down his path, but died before he could prepare the hero for the journey. It's classic mythical storytelling. In this film, with who the villain was, and the story that needed told, and to show the audience the moment he fully embraced evil... Han *had* to be the sacrificial mentor, even though Harrison Ford is by FAR the biggest star in the franchise. It was a great moment, and a powerful moment. Now that the mentor has been sacrificed, we can move to the training, and in the next film Luke can fulfill the Yoda role for Rey, and then be killed/die before the training is complete. Again, a necessary component for this particular hero's quest story.
And in film three, she will need to embrace the dark side, and then reject it (as Luke did in the Super Star Destroyer when confronted by the Emperor, to finish her mythical hero's quest. But, since her training is incomplete, the dramatic tension of will she/won't she will be heightened, just as it was with Luke, for the same reason. Then there's also the beat of her being Kylo's kin...
Both previous trilogies followed that same template, except in episodes 1, 2, and 3, the "hero" did not reject the dark side and fully embraced it to end the story. Which is why his "trainer" survived the story, and, instead a stand-in trainer (Mace Windu) was made the sacrificial lamb to launch the final act.
All the pieces were laid, perfectly, in this first film. And, it makes perfect sense. Remember in Star Wars, nothing is by chance. Every step Rey, Finn and Poe took, every move they made was manipulations of the Force pushing them to their destiny.
There was tons more thought put into this movie than the general punters are giving Abrams credit for...
