The fundamental problem with this theory is that it suggests Legends was at some level conceived as a reaction to SWSH, which I have my doubts on. For a game of its scope a 3 year cycle is the bare minimum, and assuming that's the case it would've begun early 2019. Now, that does leave them enough time to consider feedback from SWSH, but by the point that could've conceivably happened the game was probably at least in a foundational stage with the gist of its gameplay and worldbuilding laid out. In order for your interpretation to work Legends would need to have been fast-tracked into a greenlighting in either extremely late 2019 or early 2020, and that would be a very worrisome sign considering a lot of people have doubts the current 3 year cycle is even good enough for the more "standard" Pokemon games
if I had to point something out, I'd clearly pick the years of growing criticism during the 3D era which reached a boiling point with SwSh.
My theory is that SwSh wasn't the only cause, it was a catalyst.
Take for example the Wild Area. It was rough, but it shows a bit of a project, the idea of breaking free from the stiff overworld camera work, overworld mons (which started with LGPE), larger areas to explore (as barren as they were).
Aaaand, as I was about to mention a certain example... Wukong mentioned it.
I kind of agree. The concept of Pokémon without battles feels like an empty experience to me. Incidentally this is a similar criticism some have levied against BotW. For all that's been made of the open world explorative aspect, BotW does seem to lack the well designed bosses and enemies of its predecessors.
Now some say BotW was like a testing ground for BotW 2, the idea being to use the same engine and flesh out the game more after having proof of concept. Which sounds reasonable actually. Perhaps Legends has been developed with a similar philosophy. After all it's a big shift for Pokémon to move in this direction after so many years of the same tried and true formula. It seems quite reasonable for them to first test the waters with this concept before jumping in head first.
I'm sure some of you heard about a game called Skyward Sword.
The Zelda franchise, much like Pokémon, went through a bit of a fatigue period, though I'd argue it has never seen such glaring drops in quality as the 3D era.
By Twilight Princess, people were kind of noting things were getting a bit too repetitive. Sure, it *was* a great game, but it had some flaws and they definitely overcorrected on the OoT pandering.
After that, the seeds of change were planted with Skyward Sword. Hoo boy, did people bash this game.
But lo and behold. Greatness blessed our screens with GOAT of the Wild. Now, if you look back, a couple of things were in fact introduced in Skyward, namely the focus on field exploration and upgrade system. Due to the rampant bashing of the game's issues, there were quite a few changes that didn't follow through, such as the emphasis on motion controls.
Now, what does
that have to do with Pokémon?
I don't think I need to remind you about the KANTOOOOO pandering with XY after BW1 drew fire with the extreme focus on the new gen mons, but there has been growing criticism and some changes. Gen 7 tried to spice things up with Totems instead of Gyms and an evil team that wasn't actually evil. This is a clear attempt of breaking the staleness the fans were complaining about.
Gen 8, much like Skyward Sword, planted the seeds of greater change with the Wild Area. DLC expanded on it by pretty much making every outdoor area work with free camera control like the Wild Area. If you take a look at it closely, many things in SwSh were experimental, such as the TR's, the lack of any kind of natural barrier for exploration (besides the surfing bike), relying on the Pokémon themselves to act as a deterrent, raids, Dexit...
And much like Skyward Sword, it got bashed really hard. It wasn't seen as a stepping stone, especially in SwSh's case. There were high expectations for GF with their first mainline game on a home console.
Basically, I expect Legends to be good but have similar growing pains to BotW.
As great as BotW was, there was a pretty big and noticeable flaw with it, namely the dungeons. I expect Legends to not quite stick the landing, especially compared to a masterpiece like BotW.
In other words, I believe that Game Freak was already planning out the idea of an open-world game, with SwSh as somewhat of a bridge because of the rushed and troubled development cycle. They were actively waiting for feedback on SwSh's more experimental features, and had to course correct into having BDSP as a safety net instead of say, making the Sinnoh remakes
the open-world entry. When SwSh's bashing went straight up out of hand, they outsourced the Sinnoh Remakes to ILCA and fully focused on Legends, turning it into what it is right now.
Naturally, this is just a theory.