I just started playing this... Currently at level 8 and having a blast. What should I focus on? Just play and have fun until I understand what's what? I am currently just randomly painting everything.
If you haven't done so already, I'd recommend playing through the Octo Canyon campaign. It's not exactly an enthralling cinematic experience, but it does do a nice job of introducing to you the basic gist of all the various weapon classes and in particular helps you to get accustomed to just the overall control of moving around in ink and some basic positional tactics. Beyond that, just toy around with weapons, consider their strengths and weaknesses and what sort of way you'd like to play, and go from there. The particulars of the gear system and all of that won't really come into play for you until you're at least level 30 anyway so don't sweat the small stuff for now.
They don't need 2 mainline Zelda's per console, though it does happen sometimes. With Splatoon, it's become a huge franchise for nintendo with a rich ongoing content rollout. It would be foolish to let the franchise rest when it's clearly on an upswing. It's nintendos CoD, or Destiny and it deserves a dedicated team. Whenever Switch pro hits, a killer selling point would be 4 player 1 console split screen Splatoon. 4 player story coop, and 4 player online couch multiplayer. Splatoon also needs a server side account system. It also needs AI bots with varying difficulty and the ability to command them. Splatoon 2 felt like an enhanced port. Splatoon 3 on Switch could be the game to take it to the next level:
If on Switch Pro:
4 player split screen
Voice chat
Graphics bump
On standard Switch:
Server side account system
Full new game with new modes, ranking system, coop campaign, AI bots, and much more.
Keep a close eye on 2020...
Not to be a downer, but....you're not likely to get about 70% of the stuff you listed there. Improved graphics and new modes, sure. Probably a step up in campaign design given what we already saw them do with the Octo Expansion, but I highly doubt that Splatoon is going to go away from P2P connections (since that's already the basis of, what, literally all of their first party online titles?) for the gameplay itself, though maybe server side account info for gear data (at least so that we can actually use the cloud save feature for Splatoon 3, please?). Bot implementation would be really tricky and I have a really hard time imagining it would work particularly well outside of single player campaign style stuff (again like OE's faux-Rainmaker and Tower Control missions). Four player split-screen...definitely not on this hardware and not likely on any Switch Pro either.
Splatoon is a really hot property for them right now, I agree with that much...but Nintendo's rarely ever been the type to rush into fast turnarounds for their other hot properties either. There's never more than one Smash or Mario Kart or Animal Crossing on a system. Zelda or Mario you'll occasionally get more of, but those are also primarily single-player experiences where the shelf-life of the game itself doesn't have an online player-base to keep people invested. Splatoon 2 was as rushed as it was after the first game because they knew they needed a heavy-hitting property early to sell the Switch and get people into the online ecosystem, and a port of Mario Kart and a new venture in ARMS weren't guarantees at the time to spark things. Now that both Splatoon and the Switch itself are pretty well cemented, they can take their time in building Splatoon 3 to give it some more unique systems and mechanics, in addition to the typical sequel bells and whistles. They don't need to be in a hurry about it.