Books and Blacksmithing

I keep seeing fans theorize that there will be an expansion for pokopia thats an ice region since ice is currently the forgotten type in the game. While I agree (and personally theorize that it will be in Cerulean with Regice as the legendary), I keep on thinking about what else is missing which is besides magikarp and gyarados, is all of the fish. It's also missing all the crustaceans (krabby, crabawler), marine invertebrates (staryu, mareanie), and possessed ocean related things (delmise, sandygast), depsite having a beach themed location (bleak beach), and the game being about habitat restoration but the waters basically still dead space. Additionally basically all of the hms have made a come back except dive whirlpool and rock climb (the last being completely surpassed with magnet pull). This, with pokemon wind and waves coming up makes me think that there may be a region that would tie in well with the new game. Since it's already cannon that cinnabar is destroyed by a volcano in silver and gold, it could be a situation like Krakatoa where the island was destroyed and what remains of this city is largely sunk, with atolls above water and coves and coral reefs to explore below. The legendary could be Groudon who at the end of the quest line for the area would raise some of the land back above so that the city could be rebuilt, or registeel since it was a research city and the regi's are associated with explosions. Manphy/phione could also make appearances. I have no idea how to get registone included let alone the rest of the regi's though.