1) Spectating - friend matches, ranked A+ matches, team matches(after August update). Ability to have FREE Camera control and upload replays on Youtube.
2) More commands on D-Pad - "Follow me", "Fall Back", "Hold Position", "Booyaaa" would be far better options than the current ones.
3) Having Two Weapon and Gear Load-outs which you can switch inside Lobby
4) Octarians as playable characters in the different online modes
5) New Maps should include some of the platforming features of the Single Player - such as rotating areas, sponges, tubes
6) More game modes:
4 Person Free For All - the goal is to color the most area during designated time, each player is penalized heavily if he kills one of the other players while inking up the place. This will provide a different mechanic where certain players will focus on trying to ink up the environment while others try to get hit on purpose. Players see score in real time thus 3 people are able to group against one and try to get him penalized by trying to get hit by his ink.
Traversal Trials - Pretty much capture the flag in a randomly generated environment, where the different traversal mechanics are introduced and whoever captures the flag first/arrives at a particular check point wins. Since we have seen some additional environments and elements in the SP, those should be used here(pipes, obstacles, platforming). People are able to get hit and restart the course, but only long range weapons which require multiple hits for a kill are permitted.
Maze Mode - Randomly generated maze where the opponents need to get to the center and retrieve an item. Once they have the item they need to return to an entrance in order to win. But you can only traverse ground you've already inked yourself and cannot ink while carrying the item. All players are able to see the maze and colors during the game unless they are inside the center/carrying the item. You can drop the item in order to fight or ink the maze path, but when you pick it up again the map/coloring of the map dissapears - so you have no way of knowing if someone is approaching you while caring the item.
Hide and Seek - One person is able to shoot during this mode, but they have limited ink. The map starts in the color of the person who is searching. Other players are able to color the terrain as they move through it but the person searching is able to view the whole map and its is colored. So if you run into the person who is searching while coloring in squid mode you're toast, but if you color some parts and than hide further behind they might shoot into nothing. The people hiding have a 10 second head start to color some of the terrain before the person searching is deployed.