Mari isn't essential to the overall story. All the characters originally were there to represent something/embody a specific reaction/way people deal with the world. Rei-detachment, Asuka-a false front of security, Shinji-runnning away, Misato-attachment to a lover. Badass or not, Mari is just kind of there to have another hot female in the group.
I dunno. I seriously doubt Anno would make her SOLELY for fan-service catering to action and glasses-girl fans. In a way, she's also a human response to the world: just sucking it up and doing it. She doesn't seem to be the type to look back or regret her actions. And also, she's a big X-factor (among many) because until we see Rebuild 3.0 we still know very little about her. My theory is that she's a countermeasure to Kaji being a triple-agent for Nerv and/or she's a support for helping Tabris do his task.
Then we get into the entire plot of Rebuild. Is this just a movie-version of the canon Evangelion? I doubt it. I think this is the world that came to be eons after End of Evangelion with all the people we see being the descendants of the previous Shinji Ikari and Asuka Soryu (which might explain why her name is Shikinami in Rebuild). Keel is still alive because humanity wasn't wiped out to nothing, so his horrid cycle of death and rebirth is still going on (hate to be in his shoes...). Kaworu's brief moments that he speaks in 1.0 and 2.0 hints that this is all a 'redo' of some sort be it after eons or if Second Impact was redone through some strange time-manipulation (more likely the former).
Anyways, I truly think Mari is more than just a badass girl (though that's primarily why I like her).
I could go with that for Mari. Anno made each of the characters in the original series as a single aspect of himself while he was going through a severe depression, so I don't know why he would suddenly have a new insight on how do deal with the world and think it relevent to the 'remake' of an old story. Though this would make sense if Rebuild turns out to be more than a remake. But I want at least a point to Mari, I'm looking forward to what they're going to do to elaborate her. I might like her better after that. (Though Asuka is still my badass girl ) I do think that the Rebuild series will turn into something we're not expecting, Kaworu's lines and just for the way End of Eva played out make me think this. The character I really want them to elaborate on is Kaworu. For a character that only showed up one episode (likely due to gainax not paying their taxes and the series being cut short) he has quite a role in End of Eva. His name is on the mass production eva's entry plugs and he presence along with rei in shinji's mind. (though as for character development in the movies, already into the second, Shinji, Misato, Asuka, and Rei still have more backstory to be told for new fans. movies (especially action movies) generally have less time for character development than full series, which is sad)
Yeah, Kaworu was someone I learned most of what I know about from other sites and resources, and not from the canon series. I had a suspicion beforehand that Kaworu was a clone of Keele based on him saying he and Rei were alike [clones and possessing the souls of their single Angel-parents] and that before Shinji killed him he did mention that "It is my destiny to live forever" which made me think he was Keele's clone since Keele was cursed with immortality [spiiky grey hair kinda tipped me off too]. Like I said, Kaworu's brief lines in both movies have me suspecting this is a repeat of history be it Second Impact was redone or that this is the world repeating itself millenniums after Shinji and Asuka were left alone after Third Impact [which means some serious incest happened after Shinji and Asuka's kids were old enough...bow chicka wow wow]. It should be noted then that Rei no doubt has some memories of the past world she played a role in destroying as well, and may be why she seemed to be more affectionate towards Shinji this time, as if wanting to pursue the chance she could have had in the past lifetime. Hell, Unit 01's absorption of Zeruel at the end of Part 2 opened a whole freaking Pandora's Box of possibilities of how things are going to change in the series [Rei stuck in Unit 01 with Shinji and also Yui's soul? Can we say family reunion?]
I have not doubt that Kaworu is Seele's 'Rei', but why wouldn't they have just resurected him (like rei's soul keeps being transfered into different clones) to initiate third impact when he was killed the first time. This may have something do do with Tabris being the angel of free will, but if he is like Rei, when Rei 'comes back' she "does not remember". Thus preventing Kaworu(II) from having any prior connection to Shinji. That being said, Seele could have altered the previous events of Shinji ever meeting Kaworu. Having no connection to Shinji, Kaworu would not have a reason for not wanting Shinji to die an allow himself to be killed. It doesn't make sense to me why Seele doesn't do this. If the Rebuild Kaworu is a 'reincarnation', why does he make references to 'before' (something he says illudes to the past/the events will happen again). If he is like Rei (a clone) he should not remember the past, but perhaps this is one of their 'opposite' differences. Despite how similar Rei and Kaworu are, they really are polar opposites. Kaworu has free will, while Rei would follow orders to her death. Kaworu is openly effectionate (can't spell), while Rei is cold. Kaworu doesn't understand why people use what they hate (the evas), and Rei doesn't understand why they seek what they love. I think the absorption of Zeruel (if Rebuild is just a remake) was to compile significant points of the original series: Shinji being trapped in the zebra ball (can't think of his name), and Unit 1 absorbing the S2 engine, as well as 3rd impact. and according to Christianity we're all one big incestuous family anyways (adam and eve), so Shinji and Asuka being the only ones (left) on earth to repopulate would run along with the Christian symbolism that evangelion tends to like to use.