Zenos coming back AGAIN after seeming death would be just a comedy with "how many times do we have to teach you this lesson"
He fulfilled his wish, he's not a nice guy who loves to help. He's basically the WoL, if WoL didn't have his ties, friends and was only lead by pure anger, revenge and wish to fight.

Zenos got his amazing fight breaking the limits and he died happy, even tho he is so far from lifestream and Etheirys he wont be able to be reborn eventually
Let him rest already.