He's legendary because the theme of Kamigawa block was legendary creatures and permanents.
Posted By:
Nagoragama
(6/7/2011 10:41:15 PM)
If he attacks, he becomes 4/4. If he gets blocked, he becomes 5/5.
He's legendary pretty much so that you don't hook up the rest of your Samurai with extra +1/+1
from would-be multiple Nagaos.
Posted By:
AXER
(1/1/2010 7:04:49 PM)
sweet artwork. great card.
Posted By:
iantewks
(4/17/2010 12:30:19 PM)
3,W for a 4/4 creature and people are complaining? And bushido. And he's uncommon. This is a 5 star legend anyday. Anybody remember Nettletooth Djinn. Even that manages a 2 rating for same cost and it has a major drawback. Forgot to mention, pumps up Konda's Hatamoto as well!
Posted By:
console_gamer
(5/10/2010 9:10:50 PM)
Would be an okay singleton choice for any white aggro deck today I think.
4/4 for 
and 5/5 when blocked? Not too shabby.
Posted By:
TheWrathofShane
(4/24/2013 10:59:53 AM)
He was always "Nagao, Bound by Toilet Paper" amongst my buddies.
Posted By:
auriscope
(2/23/2011 2:30:15 PM)
A great card for any white deck. You dont need samurai because when he attacks he gets 4/4 and thats not adding his bushido. A cheep to play all around good card. Also i love the artwork.
Posted By:
plainswalkerKai
(7/15/2009 10:05:37 PM)
he's good, but he definitely doesn't need to be legendary. 3.5./5.
Posted By:
BrutalJim
(7/29/2009 2:38:33 PM)
the le reddit r/mtg army and its leejun loves this card! 5 stars if you agree!
Posted By:
hot4boys
(1/30/2013 3:28:44 PM)