People pulling new powers in Naruto, is sort of ok - this is how these kind of series work, and try to stay interesting (excluding here of course the main character, who only has two boring techniques, just cause)
Naruto (being one of the worst written characters in all of anime) still takes the cake though, with the ending of the pain arc. "Oh gawrsh, you're the hero, guess you'll hit me now, with a technique I have shown to easily dodge, and shrug of. Oh, and now that you totally convinced me WITH DA POWA OF FRIENDSHIP, let me just ressurect every character I killed off, and die in the process, completely sucking any moral dilemma or impact from the last thirty episodes"