This made me laugh. Thank you.
Fun note: In the Godzilla comic series, Zilla and Godzilla meet in Honolulu and have a brawl. Zilla really used his agility to run rings around the Big G, getting in blows and retreating before Godzilla could retaliate, but the ending was a foregone conclusion: Compared to the kaiju that Godzilla fights on an everyday basis, Zilla just can't really do anything to Godzilla, and Godzilla gave him a sound thrashing. But the comic really give me a new respect for Zilla. He really put up quite a fight for a hopeless underdog and was cunning enough to recognize and exploit his few advantages. Zilla ended up retreating, but only when he was at death's door.
I think Zilla would make a great addition for Godzilla's gang of Earth-defending monsters on Monster Island. He'd be the weakest club member (maybe he could Anguirus' place as the series' woobie and spare the poor guy from getting whooped every time he steps onscreen) but like Godzilla he's a protective parent who has no real beef with humanity or interest in destroying/conquering the world. He's not dumb and he loves to destroy him some cities, but he's also not power-hungry like Destroyah and Orga or into dominating Earth like King Ghidorah and Space Godzilla. In other words, he'd get along well with Godzilla and Mothra and the like if they could get over the attack-on-sight mentality.
Or maybe Toho could just give Zilla/Zilla Jr. his show back. They could test out monster ideas with the enemies and cement Zilla's place in the Godzilla universe, wherever that may be.