I figure Asuka will probably have her biggest role in the Rebuild franchise in FINAL.
But, I think based on the trajectory of the narrative of the narrative and what has been set up dramatically in the past three films the central leads of Final are going to be Shinji, Rei (both versions) & Misato. Rei & Misato are the two characters Shinj had the most emotional connections built up with in the first two films and those are also the two characters he most likely needs to reconnect with after the trauma of 3.0.
Misato needs to commiserate about how she feels guilt for what Shinji's life has become due to her flaws in guidance starting in 1.0.
And then he'll reconnect with Classic Rei when he steps back into the Eva.
Rei Q is the mystery for me....
I'm almost certain that Anno did not want this, but he has turned Rei Ayanami into a Four Murasame 2.0, or even into the "lalah sune" of Shinji , in some way that he could not have foreseen (or maybe yes, Ship taste
* Lalah sune was the romantic interest of Char Aznable (also of amuro ray), being this a replacement of the mother of char, granting her a place of peace and tranquility, lalah sune also has the rare powers and the whole spiritual roll.
Basically, when improvising the plot of the films, it has ended with a configuration in which the characters that have been "important" have been reduced.
just kaworu, Rei, Misato, gendo ;Leaving aside most of the shinji-asuka dynamics (hard to recover in 3.0 + 1.0) , S / A depended on a stormy relationship, with sexual subtext.Shinji in a state of depression or apathy does not allow this (that and that is the last movie)
* could make a more conventional love relationship but I do not see a reason to do that, except to please the fans (making everything feel like a fanfic, I'm not sure that some are aware of this)