Water finally gets a reliable draw power card with Teacher and Pupil.
Now, a lot of players might complain about this card's Entrance Cost, but let's not forget that One Morning (you know, Wind's OLD draw power card?) was also a 4EC Mission, and it did pretty much the same thing. Of course, TAP also has an effect that takes advantage of Water's anti-Chakra tendencies, kicking you an extra card if your opponent's running low on Chakra. Three cards on Turn 4 - one is hard-pressed to do better, especially with Water.
Some might also argue that draw power actually works against Water's current mechanic (Empty-Handed builds). Well figure, with that deck, you'll be dumping most or all of it into Chakra anyway - why not give yourself that many more options? That's what Ambush and play-from-Chakra Jutsu are for! And let's not forget, you'll need cards in hand to power the new Discard builds. This will also be good in Void decks that splash sufficient Water - especially if you can move your Turn Indicator up early and get this out even sooner. All in all, a flawless card, and definitely one we'll be seeing a lot of in tournaments to come.