LC, not to be a dick, but what makes Zone Fighter different from Jet Jaguar? I've never seen the Zone Fighter show, so they seem like pretty similar characters, especially since they're both inspired by Ultraman.
"New" monsters I'd love to see, roughly in order from most wanted to less wanted... though honestly, I'd be psyched to see any of these guys:
Hedorah for sure-a. One of my favorite monsters from one of my favorite movies. I appreciate that Pipeworks had big ideas for portraying this monster, but not being able to achieve those ambitious plans shouldn't have made Hedorah drop out of the game completely. Final form Hedorah is all I need!
You could argue that they're only tangentially tied to the Godzilla franchise, but Baragon does a nice job of bridging the two movie series. Again, these are some of my favorite monsters from some of my favorite movies. As big hairy humanoids, they'd do a great job of diversifying the mostly dinosaur/insect/mecha cast, and their movie battles demonstrate fast, furious monsters that would be a blast to play as.
Don't judge me. Small, fast and weak: the ultimate joke/trolling character. Minya's grown on me a lot over the years, and he really is an important part of Godzilla's legacy. Smoke rings forever!
It might seem strange that I'm listing Zilla, since I'm not a fan of his original movie. But he's a very cool looking monster, and I loved his bit in Final Wars... I think seeing him blown to smithereens by the real Godzilla put Zilla up a couple notches in my book. Plenty of Godzilla fans (myself included) would love to give the big iguana a rematch, and see how he stacks up to more veteran Toho beasties.
Surprisingly one of Godzilla's deadliest foes, and would be a MAJOR change of pace compared to the other relatively humanoid monsters in the game, and even compared to the insectoid monsters we've seen in past games. Kumonga would probably be a bitch to program and animate, but man would it be an impressive, unique monster. Bonus points: if they can crack Kumonga, it'd probably be pretty easy to cook up Oodako, another one of my favorite B (well maybe C) list monsters.
Like Kumonga, Manda would be a challenge to program and animate, but damn he'd be a cool, unique addition to the monster roster. While he's never had the star power of Toho's big 5, he's been all over the Toho-verse.
I can take or leave Kaizer Ghidorah (actually... let's leave him, there are a lot of cooler Ghidorahs out there to choose from) but Monster X is a bad-ass who deserves another shot. A freaky, horn-headed skeleton-alien-man that shoots lightning out of his eyes? Yes please!
Another star from Son of Godzilla, Kamacuras would be another insectoid monster. However, he'd be wildly different from Toho's flight-based bugs (Mothra, Battra, Megaguirus), and still very different from the extremely anthropomorphic Megalon. The addition of invisibility powers from Final Wars really make Kamacuras stand out from the rest of the buggy pack. Plus mantises are awesome.
I really love the idea of the next Godzilla game pulling in creatures from other Toho monster flicks (though like the Gargantuas, Gezora DID get a quick stock footage cameo in Final Wars' opening credits...). Space Amoeba is a favorite of mine, and Gezora is by far the most fun monster from that movie. While he wouldn't be the easiest to program or animate, I'd have to think he'd still be simpler than say, Kumonga. His delightfully goofy appearance and weakness would probably make him a fun joke/troll character, ala Minya.
While Godzilla's Revenge/All Monsters Attack isn't exactly a unanimous fan favorite, Gabara was easily the best part of the movie: a strange, ogre-like bully of a monster with tons of personality and a cool electro-grip attack. Like Monster X, Gabara deserves another shot.
Wow, 10 monsters! It's a lot, but I think all of these guys would contribute a lot to a new Godzilla game, and do a lot to keep the monster roster fresh and exciting. Seeing any of these monsters in the next game would be fantastic, but if I had to pick one, it'd be Hedorah, no contest.
Haters gonna hate