Splatoon was one of this generation's most pleasant surprise for me, and judging from its unexpected and explosive success, it would seem I'm not alone. From its quirky sense of style to its fantastic feeling movement mechanics, it's an excellent series debut.

Having said that, I think it has the potential to grow immensely as a franchise, and here's some of the things I'd like to see added or improved in the all but inevitable sequel.

Bot games: The ability to set up and play Turf War or other kinds of matches against computer-controlled opponents with a high degree of customization for things like difficulty, loadouts, etc. Should be player in single player and both local and online multiplayer.

Horde mode: Gears of War style against escalating waves of Octolings, once again playable in single player, local splitscreen, or online multiplayer.

Online splitscreen: The ability to play online matches with a friend on the same system, a la Mario Kart 8/Wii.

4-team matches: 16 player Turf War with 4 teams instead of 2.

More than 2 maps per mode at a time: Self-explanatory. 

Longer single player campaign: I thought the single player in the first game was fantastic, but it was a little on the short side. 

What things would you like to see added in Splat2n?

A good local multiplayer mode.
Not having to leave a lobby to change weapons. Either let me change weapons before the match starts (like in Squad Battles or whatever), or let me change weapons mid-game.
Voting for stage system like in Mario Kart 8.
Inkling and Octoling singleplayer campaigns (therefore, Octoling as playable characters).
A bigger hub world, but with the same style (in an urban city).

Multiple sub weapons in online battles like in the single player mode.

New sub weapon Gravity Bomb like splat bombs that sucks in all enemy's and ink caught in singularity.

Super weapon Missile Launcher that works like an Inkzooka that fires one shot in what ever direction to the end of the map laying down ink as it goes. Including up. Killing any enemy caught in it's path. Since it's one shot the ink should be about twice as wide ad an Inkzooka shot.

Some type of Missile Launcher main weapon simular to Ink Launchers with out having to load up but requires enough ink to launch a missile

I just hope they have co-op multiple for online play. Not having the ability to play online with my daughter just doesn't make sense given how family friendly it is. I understand that the whole super jump thing got in the way, but I'm sure there's a work around.

Btw... greatest shooter this generation hands down.

Splatoon's singleplayer was tons of fun, so a longer campaign for Splatoon 2 would be welcomed. I would also like to see the mode rotation in Ranked Battle GONE. Rainmaker is my favorite RB mode, but I can't fully enjoy it because most of the time I have to choose between Tower Control and Splat Zones! More maps in the map rotation would also be great. There are other things I would enjoy, but those are the musts.

Better matchmaking without the annoying wait-for-2-minutes-when-joining-and-disconnecting-right-after mode
Better map rotation/selection
Clans
Remove Spyke
Higher level cap
Players vs Bots
Single player turf war

Friendlier online co-op. The way to play with a friend in regular mode right now is rediculous.

My first things was going to be voice chat, but really that should be a console thing, not a game thing.

Being able to change weapons between battles. That's about it. Love the game otherwise.

Is this an announced thing? If not, "Splat2n" better be out the title is written.

I love Splatoon like it is, only I want from Splatoon 2 is 4-team matches.