– 12 Captains, with each their own attributes.
– Bowser is a new playable Captain this year.
– For the first time you can mix and match sidekicks in your team.
– Boo, Dry bone, Shyguy and Monty Mole are new sidekicks.
– 9 new Stadiums, each with their own events. Such as no sidewalls so you can push the other team off the field.
– Each Captains have their own special ability.
– Sidekicks each have different skill shots.

Online play
– You’ll be able to play ranked and unranked games online.
– Playing 2 players locally on one Wii against 2 players on another Wii online.
– Season, each season is around 3 months, during those three months it will keep track of all your win/lose and the points you’ve won.
– Striker of the day mode. If you’re get the most ranking point in a certain day, your Mii will be featured on everyones Wii.

Friend Code
– You import your Mii in Strikers, and get a friend code per Mii. This way, you and your family can have different friends to play with online

Source: 4colorrebellion