I think its pretty unfair to say Alleluia's role is anywhere near done in the story. I'm pretty sure we have yet to even see the Gun-Archer in action and its pretty blatant the most likely pilot for it is going to be Maria. As such sooner or later he needs to accept she wants to fight by his side and they are the most likely of the meisters to end up dead for there combined sins. The only reason it might seem he's had a small role lately is he had a major arc and the other 3 are simply getting back some missed screentime to develope them.
Songs were never at any point used as weapons in Macross 7. In Macross 7 yes his music would cause the enemies to flee but never because it was hurting them in fact it was because they couldn't control the orgasmic response they were having from it or because it was breaking the Mind control on them.Originally Posted by Ryllharu
In Macross and most of them its used as a means of culture shock to confuse the enemy and either cause them to give up on fighting or keep them confused and unorganized. Its very loosely a weapon as it doesn't actually kill anyone on its own. Also the fact remains "culture shock" is the actual thing that could be considered a weapon Kissing, Beauty pageants and anything else that would be considered culture had the same effect singing was only focused on because they could attach a person to it. Still song isn't a weapon.
In Gundam on the other hand music is generally used to draw people to your cause. In seed Lacus was always used to rally the troops with her music and later when they replaced her with Meer Campbell it was the same reasoning.
Its very fair to say this situation with Maria and the children singing is much closer to how Macross has used music. Kind of a unite the world with music kind of angle instead of a rally the troops one. Using the OO-raiser to actually spread her music is even more of a Macross thing as in Macross 7 and Macross Frontier they would use Battleroids to actually amplify the music so the enemies would hear it. Using the OO-raiser is about the equivalent to using a Macross class ship to blast out music as done recently in Macross Frontier. So essentially assuming Maria and the Children's song if used to bring people together and put a end to war is very blatantly a rip off of Macross.
So essentially what I'm saying is you have the roles of Macross and Gundam COMPLETELY reversed. Macross singers are all people who actually became singers the ability to use there music during a battle comes after the fact and it is not the reason for the music in the first place. The singers in Gundam well in Gundam Seed anyway I can't think of any other gundam using singers in a major role at least. Are used specifically as tools to support the war. That is the only reason Meer even exists in the first place and what Lacus was used for until she met Kira and looked into things at least.