http://na.leagueoflegends.com/news/nami-tidecaller-revealed
I like what I see of ^ so far. the idea of magic bouncing around between champions and healing/damaging 'em depending on friend or foe seems real fun, and real useful. Not to mention mass area slow effect ultra and adding slow to allies' attacks.
Made it to level 6 so far. I see what people mean by assassinating. Just waiting out of sight for a champion weak enough for you to batter with your arsenal and slowing 'em down so they can't run away effectively. Or in rammu's case, make 'em turn right back around to attack you with his taunt. Definitely using better summoning spells than teleport one and quick revive.