In response to the OP, and to others who have put the time into getting their Zeta: Nothing can take this away from you, and unlike me, you got to experience your Zeta while it was the most powerful weapon in the game. I have so much admiration and envy for you guys.
I am doing the questline because it is interesting, and because I want at least a taste of what you guys went through, even if the grind has been nerfed. Doing the Animus upgrade which I believe has not been changed was without question the hardest part for me thus far. You couldn't get me in three dungeons a week, and I was doing three dungeons a night; I even soloed Aurum Vale @ iLv123 to test my solo ability, and because I have this OCD thing with avoiding exp points. It really pushed my anxiety limits to the test as a healer, and I took two nights away from the game to regather myself after the books were finished.
You can get a replica, sure. But all it says is I got this cool glowy weapon in the easiest manner possible. You examine someone and see that their Zeta version is not a replica, you KNOW they wen't through some shit, and a lot of it. As far as becoming obsolete so quickly being only iLv135; it's all about perspective. And from my perspective, I like to think that my Zeta continues to consume energy. It eats every codex proceeding it under the guise of a glamour!![]()