A lot of people seem to be disappointed that Ren wasn't scary impressive like Vader but I think that was the point. Trying to copy an iconic character like Vader can just end up hollow at best and embarrassing at worst. A lot of people coming into Star Wars without a huge knowledge or love still probably know what a Star Wars Villain is supposed to act like. So they pulled a switcheroo on the expectations of Kylo Ren like a third of the way through the movie.

He's the counterpart to Rey, who runs from a legacy that she feels is too big for her while Ren desperately tries to embrace it but has BIG doubts he's large enough to fulfill it. They deliberately make Ren seem like a badass in his first scenes, but once act 1 is done you see Ren for what he is, which is exactly what's underneath the mask. He gets shit on by Space Nazi Bill Weasley in a way Vader would never have had happen. There's a scene where Ren is talking to Snoke without his mask and Hux comes in and Ren kinda has an expression on his face like "shit I need to put my mask on I don't look scary at all crap too late."

I don't think he was every supposed to be the new Vader. It all seems too deliberately designed to make you think yes these guys are Empire fanboys cosplaying and Ren is the biggest dork of them all. He has a ton more interesting bits to him as a character than Maul every did aside from some cool ink, a shiny lightsaber and some dance moves.

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Oh God, it was me. I was the grognard all along.