Well this thread has been inactive for about two years, and I've been inactive for about as long, but I was thinking about this earlier today for whatever reason, and have sort of a new spin to add to this thread; Not changing the plots of the movies as much, but adding thematic depth to some franchise entries that are lacking in it, and cutting out certain decisions that were made in the interest of money, preserving the artistic integrity of G54:
SHOWA CONTINUITY
Godzilla: Why make literally any changes? It's damn near perfect, and without it this thing that unites all the people on this Wiki wouldn't exist
Godzilla Raids Again: I've always felt that this movie kind of knows that it doesn't have a reason to exist beyond the fact that Godzilla made a ton of money and Tomoyuki Tanaka demanded a sequel, but here's my take on how it should have been approached: The best of humanity (Serizawa) makes a sacrifice at the end of G54, but nature always strikes back. The universe is unknowable in scale and in vastness of power and cannot be put down, so Serizawa's sacrifice is ultimately in vain as Godzilla returns, and this time he's not alone, as Anguirus appears at the same time.
Rodan: Leave it be
Varan the Unbelievable: This is the first film where the military might of the growing JSDF is really emphasized, at a time when another World War looked all but certain. Varan's vanquishing should be a celebration of the fact that Japan has the military might and ingenuity to do what needs to be done to protect themselves
Mothra: Leave it be
King Kong vs. Godzilla: Wowee, we sure got to the silly and commercial ones quicker than I thought, but KKvG has such a charm, I can't bring myself to change much of anything about it. Making it a serious piece of high art would almost detract from what makes it enjoyable.
Mothra vs Godzilla: Godzilla's first encounter with the protector of Infant Island is pretty thematically light but very focused, and I'm fine with it staying that way.
Ghidorah the Three-Headed Monster: This is a little bold: Godzilla has traditionally been a symbol of nuclear destruction and, by extension, the consequences of the existence of nuclear weapons. So maybe this can be the film that finally reconciles the fact that nuclear weapons are part of our world now, and they won't go away, so maybe they can protect us from bigger threats that we can't always prepare for. These potentially cataclysmic acts of hostility by foreign powers can take the form of Ghidorah, which Godzilla and all of his nuclear allies must band together to confront, to prevent the end of the world.
Invasion of Astro-Monster: Just a thematic continuation of what was set up in Ghidorah
Godzilla vs The Sea Monster: Just let it be Operation Robinson Crusoe: King Kong vs Ebirah, like it was originally intended to be
Son of Godzilla: The first of many meta-commantaries, commentaries on the nature of the Godzilla movies themselves, reflexive commentaries, if you will. Basically, for Godzilla, going on fifteen years old as a franchise by this point, to continue to thrive, it needs to evolve, sybolized on dual fronts by the emergence of Minilla, the literal evolution of Godzilla, and Godzilla's arc as far as growing to care for Minilla, growing into and accepting the role of hero and protector
Destroy All Monsters: Leave it be, it's a f****** classic, an absolute delight. But this is the end of the Showa Era as I see it thematically.
GODZILLA'S REVENGE: To tell you the truth, I'm at a loss for how to approach a couple of thelater Showa era films. I'll leave this one be.
GODZILLA VS THE SMOG MONSTER: Ditto
GODZILLA VS GIGAN: There's this idea that the Space Hunter Nebula M aliens are trying to save the Earth from humanity, which I would like to see explored a little further. Maybe Gigan isn't as sadistic, maybe there can even be a sympathetic facet to him that could add both to his character (though it would modify him significantly going forward) and to the thematic depth of the film
GODZILLA VS MEGALON: Perfect. Best movie ever made. Don't change a thing
GODZILLA VS MECHAGODZILLA/ TERROR OF MECHAGODZILLA: End the Showa era one a positive note. Godzilla fights for Earth and for humanity against his counterpart from a supposedly technologically-superior race, but he comes out on top not once but twice. In the vein of how Captain Marvel is a celebration of humanity and human individuality (it is, shut up), these films can do basically that.
HEISEI ERA
Return of Godzilla: Leave it be
Godzilla vs Biollante: Leave it be
Godzilla vs King Ghidorah: The only change I would make is that maybe it should be a deeper dive into Japan's place on the world stage, and how a shift in that would bring about a thing like the Futurians doing what they end up doing and (spoilers) trying to destroy Japan and nip the burgeoning economic power in the bud. How? I couldn't tell you, I'm not an expert in Japanese economics and geopolitics circa 1991
Godzilla vs Mothra: A pretty incurious and shallow environmental message bogs down this film. I'd retool it by returning Godzilla to his roots and making him nature's revenge against the folly of man, with Mothra rising as the more maternal, nurturing natural force that will protect and guide humanity down the right path. And for the love of god, give Akira Takarada something to do
Godzilla vs Mechagodzilla II: A melding of the themes from the previous two films, in keeping with how, like GvKG, a mecha ends up having to protect humanity from Godzilla, and, like GvM, Godzilla is back to being a pure villain again. This, I feel, could turn it from one of the least sophisticated films in the Heisei Era to one of the most interesting (even if it doesn't turn out good)
Godzilla vs SpaceGodzilla: Strike it entirely from the canon, honestly. It really holds no thematic value, in my eyes. I really can't stand this movie.
Godzilla vs Destoroyah: The erasure of GvSG means that this movie can come out in 1994 and be a fitting 40th anniversary tribute to Godzilla like it deserves.
Godzilla '98: I need this film to continue to exist so the Millenium films can act as a direct refutation of it
MILLENNIUM ERA
Godzilla 2000: Millenium: This film opens with true blue Godzilla, with a really great slow-burn sort of intro. Lean more into that, maybe a sort of horror-driven edge to Godzilla, and a real focus on the classic elements of the character. Show Dean Devlin and Roland Emmerich how it's done
Godzilla vs Megaguirus: I'm open to suggestions. This is another one that, like SpaceGodzilla, has always felt a little hollow and worthless to me. I'm open to suggestions on how to go about fixing this one, I don't know where to begin
GMK: I may not love everything it does, but it goes for a lot of different ideas regarding Godzilla as a manifestation of revenge and grief that I feel goes a long way toward reintroducing the classic ideas of the franchise for the 21st century
The Kiryu Saga: I'm going to share with you all a comment I left on Up From The Depths's review of Tokyo SOS (check out his videos if you're not already familiar, he makes wonderful content that has had a lot of influence on the way I approach writing about Godzilla (something I do a lot these days):
I think we share some of the same frustrations as far as the 'Kiryu Saga' is concerned: They're visually spectacular and brimming with potential, but shallow in pretty much every regard besides visual. I had this thought while I was listening to this review, an idea of what these movies could have been, that might have alleviated our frustrations. Imagine Godzilla Against Mechagodzilla as a meta-commentary on the direction the franchise has taken. Mechagodzilla is literally a perversion of the remains of the original Godzilla, there's so much thematic potential there as far as the state of the franchise in that concept, and could go any number of ways. And then, instead of rushing Tokyo SOS out for a 2003 release, make it the golden anniversary of the G-Man. This would serve the dual purpose of giving the filmmakers time to craft a more engaging narrative around the monsters, and sending a message for Godzilla's 50th, the same one the Shobijin are sending to the human characters of Tokyo SOS; Out of respect for Godzilla, it's time to let him return to the sea, to put him (both as an in-universe being and as a franchise) to rest.
I know it's long but I like to think it's worth a read
BECAUSE OF THE PREVIOUS CHANGES, GODZILLA: FINAL WARS DOES NOT EXIST
Godzilla (2014): Let it be
Shin Godzilla: My ideal Godzilla film in every way. Don't change a single thing
Kong: Skull Island: I'm totally fine with the idea that thecurrent wave of American kaiju films can exist as a love letter to what came before, and the MonsterVerse's first universe-expanding entry achieves this at every turn
Godzilla: King of the Monsters: Ditto