I hope they don't have Godzilla fighting other monsters in this one yet. You gotta have him be a threat to humanity first before he can become the classic anti-hero.
My perfect setup for a trilogy would be:
First movie focuses on Godzilla being created and attacking the city. Humanity throws everything it got at Godzilla but it bosses itself through everything. At the end they find out Godzilla only came to land to take out the corporation that had been polluting his home turf (ironically the pollution that created him). Reluctantly, they let Godzilla return home.
Second movie would be an arms corporation trying to capture Godzilla (nod to King Kong) with advanced weaponry so they can find out the secret of his mutation. After beating them, Godzilla, pissed that humanity wouldn't leave him alone, returns to land to lay some more waste. But the government was never sure that Godzilla would remain peaceful and release their new weapon... Mecha-Godzilla. After Godzilla nearly destroys MG it is revealed it runs on a nuclear core, and its destruction would be catastrophic. Godzilla realizes the threat and its danger to the innocent humans, and throws MG to an uncivilized island in the ocean, where it explodes.
Third movie would be researchers exploring the devastated island and discovering that all the wildlife has mutated, which cues multiple monster cameos (Mothra, Anguirus, etc.) although most of them are indifferent about the human presence and worship the carcass of Mecha Godzilla. Until they accidentally awaken King Ghidorah, who lays waste to the island and flies off to the mainland to cause more shyt. Godzilla knows this but lets it happen because he hopes the human race will finally learn from their mistakes. Instead, humanity releases a rebuilt Mecha Godzilla on King Ghidorah. Realizing that this could repeat the catastrophe he reluctantly prevented before, Godzilla joins the fight against King Ghidorah, if only to prevent Mecha Godzilla from exploding. Even with their combined strengths, Godzilla and MG can't beat King Ghidorah, although Godzilla is severely handicapped because he needs to protect MG. The other monsters, who stayed out of the battle so far, recognize in MG the reincarnation of the 'god' that gave them life, and join the battle. With them protecting MG and serving as back-up, Godzilla can finally take the fight to King Ghidorah and beats him, officially becoming the king of monsters. As a final warning he scorches the battlegrounds with his crew of monsters, so humanity knows that although he saved them time after time again, he will not tolerate their bullshyt.