Here's what I think the theme for Sun & Moon is...

[Hikamaru]

With the confirmation of Alola Forms, Rockruff's evolution and the huge focus on nature in the Alola region, I believe the theme of the games is Darwinian Evolution a.k.a taking on different forms to adapt to the climate. Pretty much, the theme of the game is all about focus on alternate forms and adaption.

Alola Forms we've seen so far involved the Pokemon adapting to the very tropical climate (Exeggutor), becoming nocturnal (Rattata line) or the snow-topped mountain after being forced to run from their home (Sandshrew and Vulpix lines). Rockruff's evolution adapting a different form based on what time of day it evolves at might also hint to how different the climate of Alola acts at different times of day.

There's also the Ultra Beasts which have been speculated to be the real forms of characters we have seen, like the theories going around that mention that Lillie is actually UB-01. Another new Ultra Beast revealed today is also likely gaining speculation for actually being Lusamine. While they don't seem to be taking on their "human" forms for climate adaption, they seem to be doing it for a purpose - to find out about Alola's climate and use it as part of their plan. Especially when you consider the "Aether Foundation are the villains" speculation as well.

Who agrees with my theory here? Does this give you hype for more Alola Form and evolution ideas?

 

[Hikamaru]

I'm a bit hesitant to believe that UB-02 is Lusamine, although I definitely feel there may be something shady about her. I dunno; I feel like it's a stretch to claim that she isn't really a human but an alien thing. :s

You do have a point here, but considering Lusamine, Gladion and Lillie have the same blonde hair/green eyes thing it would be no surprised if they all had a connection to Ultra Beasts. I'm also on the bandwagon that says Ultra Beasts are more like alien beings that disguised as humans, which definitely suggests them as the real villains rather than Team Skull.

 

[Lunar]

I definitely agree with this theory, so far the recurring theme behind Sun and Moon does seem to be adaptation in order to survive. There's so many routes that Game Freak could go down with this theme and the climate could affect each Pokemon differently allowing for a great variety of evolutions and Alolan forms.

 

[Caaethil]

I think this is really too specific and kind of obvious. A much more broad theme is nature. Darwinian evolution is a part. But so is conservation, which we all thought of back when Komala and Rockruff were first shown. And of course, Alola is such a tropical place full of nature. Perhaps a more appropriate theme would be the world around us, how varied and beautiful it is in many ways, and our relationship with it. After all, we have Z moves, which emphasise bonds with Pokemon and all of that cheesy nonsense. On pokemon.com, Ohmori says that the names Sun and Moon were chosen due to how the Sun and moon work to influence the world around us. Both are needed for our world to exist as it does. It's all about balance, and an ecosystem, which will probably be presented in a "Work together kids!" kind of way.

 

[Starry Windy]

Personally, I'm agreed to many of these theories, including the one involving Alolan forms to adapt to the climate. And as for me, I think Game Freak might want to showcase how people, Pokémon, and everything around them are able to co-exist in many ways and able to live with each other, given how abundant Alola region as we've seen so far. Granted, I don't quite understand how Ultra Beasts will play a role in Sun and Moon as of yet, but if several theories involving UB are correct, I'm wondering if they're disguising as humans so that they can observe and want to get along with them? I guess this means there's a lot to speculate, then {XD}

 

[Hikamaru]

I think Caaethil has a point. Nature is very rich in Alola and I feel that is definitely playing a part in the theme of this game.

 

[Attribule]

The theme this generation seems to be "Natural vs Unnatural"; "Organic vs Artificial". This fits in with the grander theorized theme of "Evolution".

Evolution can be natural or unnatural. Examples of natural evolution are obvious, so I'll give an example of an unnatural evolution: Androids

A common belief is that machines could become so advanced that they "take over mankind, possibly leading them to extinction". This is unnatural evolution. We invest more in our technological advancements instead of personal, organic ones, therefore our next logical evolutionary step is no longer "natural". Machines, or androids in this case, would be what we "become". Much like the beings that we evolved from died off and "passed the torch" to us, we would do so for our successors, the Machines.

Alola region is the strongest in terms of natural life -- completely unrivaled so far. It has an abundance of all nature, and has caused many species to evolve in shocking ways.

Aether, possibly even others, contrast this with their man-made, unnatural creations. They force their place in the landscape, creating an island themselves. They force life and evolution into existence in the forms of the UBs and Type: Null (possibly more).

The region ultimately becomes simultaneously the richest natural and unnatural one we've known so far. The natural life trying to live on and evolve in its way, while the unnatural life tries to do the same for itself.

 

[MarinoKadame]

And I guess Zygarde is not that happy about that and will go Complete form to bring back balance.

 

[OmegaRuby and AlphaSapphire]

I feel like they're moreso creations either by the Aether Foundation probably by accident to cause **** for people and Pokemon.

I prefer that they aren't creations, but rather are aliens.

Perhaps the UB aren't actually antagonists. Perhaps they're looking for a new world, but are attacked by those who fear them, like how Rayquaza feared Deoxys in Destiny Deoxys.

 

[Hikamaru]

According to TheOneIntegral, he believes invasion may play a part in the theme as well, as explained in this video:


Stuff he brings up in the video are Yungoos and Meowth being invasive species (we already know about Yungoos, but you get the idea) and how the introduction of Yungoos saw the native Rattata adapt. Meowth were apparently imported from Kanto by Alola's Royal Family. The Meowth started becoming breaking out and becoming Dark-types inhabiting the island.

He also mentions Team Skull who are rebelling against the traditions of the Alola region, and we also know about how Guzma was rejected from being a Trial Captain, so the Team Skull members are rebelling and trying to take over Alola. Then there's also the Aether Foundation who seem to have played a part in the creation of Type: Null as well as Ultra Beasts invading Alola. Ultra Beasts have also been speculated to be human-Pokemon hybrids. The official website also mentions how Ultra Beasts are posing a threat to Alola.

Heck, even the protagonist can be considered as "invading" Alola since he/she moved from Kanto. Alola's basis on Hawaii also ties in with how Hawaii is getting taken over by invasive plants and animals in real life. The species in question are threatening the unique plants and animals to the area, which is likely the case for in-game Alola as well.

 

[Esper]

I do like the idea of a theme where you have this balance of adapting to your environment vs. adapting the environment to you. It's a very ecological theme and goes well with the idea that lots of Pokemon this generation are designed based on endangered species.