I can't wait! I rewatched it, and they specifically said "new" weapons. New variants? If we get 4 weapons per month now, and I assume that's going to continue, that's like 12 new variants with their alternate sets (including Explosher and Ballpoint and the missing variants we still need)!
However, I feel as if Nintendo needs some more creativity with their stages. It feels like most of them are just rip-offs of old stages (Albacore = Mahi, Snapper = Bluefin, Humpback is like Blackbelly, etc.) Some interesting mechanics that I would like to see from these stages would be grind rails instead of ink rails so people can't just back out of an ink rail when they see danger. Also, Rolonium generators would be fun, but maybe a little complicated as people would just camp there.
A different approach would be to refurbish old maps to get new things like how they did with Urchin Underpass in Splatoon 1. They could take some of the hated maps (Moray, Starfish, Humpback, Shellendorf[?]), and add new things to them. I would like to see more movement options for Starfish and Moray, and maybe someways to easily get back into the action without getitng spotted for Humpback and Shellendorf.
Furthermore, when they mean maps, I also hope they give some love for Salmon Run! Having Saltspray Rig return for it would be phenomenal, but I don't know how they would turn it into an interesting map. Adding on, if they were going to update Salmon Run, maybe add some more events and bosses? I would really love to see more events like the Mothership or Griller. New bosses based off of specials like bomb launcher and bubble blower would also add more challenge and variety to the game mode.
Another thing to highlight is the possibility of new gear. Tentacles Helmet is still unreleased, and there seems to be a large lack in styles that Nintendo can use, but we alreayd have so many differnt pieces of gear, and with Murch and SplatNet, abilities don't really matter anymore, so it might not be as likely.
Finally, they said that Octo Expansion would be the first DLC of Splatoon, which implies that there might be more. I don't want to spoil anything, but the ending of Octo Expansion left a few strings hanging that totally could be used for another DLC. But what would be the reward? Playable Octolings were already major enough, so how would Nintendo persuade us to spend probably another $20 on DLC?
Overall, I'm excited on what Nintendo has in store for us, so I hope I didn't set my expectations too high. Feel free to bash me with all my grammar errors as I didn't reread this.