It’s close between Kalos and Galar - the former for being so linear with so little post-game, as well as being so easy - but Galar takes the cake. The story there is the worst in the series by far - even worse than the Kanto region’s barely-there story - thanks to its focus on Hop and Leon, its flimsy villain motivations, and having several moments where it literally tells you “don’t worry, player, you don’t have to be involved in this plot moment because the adults are here!” Leon to the off-screen rescue, I guess? That Leon was shoved into the anime with the same not-believable, Gary Stu’d “unbeatable” gimmick means that the negative experiences from Galar now also pervade a second medium, and in a way that has actively done a disservice to multiple other Champions. It’s also an incredibly linear region outside the Wild Area, which itself is limited in scope, and the $30 DLC. There are entire “towns” that are a single narrow corridor with a backdrop, there are dozens of buildings that are just props, and the Battle Tower is supremely unchallenging. The overall aesthetic is also nothing special, which is another reason Kalos edges it out in competition. I have felt not a sliver of joy or happiness engaging with that region - Kalos, at least, is nice to look at.
I have to mention that Kanto was also in the running for just generally being quite blind, but it has a certain nostalgic charm nonetheless. I also have to throw mildly-dishonorable mentions to Alola for being similarly linear and Unova for introducing by far the worst Pokémon designs in the franchise, from my perspective, but beyond those items I feel they’re leagues ahead of the other two here.
Alola honestly suffers from not allowing the water areas to be more traversable like Hoenn; that would allow them to significantly reduce its linearity and introduce more small islands throughout. It probably has the most potential of all the regions in the bottom half of my ranking, and it’s a shame that it was ultimately so limited.
