I've watched up to episode 15-20 of Shippuden.. they stopped being ninja's around episode 10 of the original.I love Garra, but that is in no way a ninja...

Ninja's operates in the shadows quickly, decisively, and quietly avoiding detection, killing their target and escaping as if they were never there. THEY DO NOT, go about blowing shut up screaming out their magical "skills names", ninja's don't name every little ninja thing they do. They do not go rushing in to their target seeking to confront there target head on, that's what honorable Samurais do (the civil declaration of a duel part). They do not have huge and flamboyant competitions to prove who is the top ninja. They rarely use kids for assassination, they can't hold their own against a number of adults guards/samurais and scale walls as easily as an adult. They can not jump 10 stories high and fly. They do not summon 20 story tall monsters nor tame such beings. They do not have control over death. There is a very limited set of animals they can tame abd use for missions. They can not jump into other peoples bodies. They die when they are killed. They die when they receive fatal wounds. They do not have magical healing abilities. They can not perform (FMA's) alchemy like transformations of objects. They can not manipulate sand, water, fire, etc. as extensions of their bodies. As many players feel hard to level Ninja, you can buy DFO gold to get good weapons, mounts, and armors in DFO journey.

I'm not hating Naruto, I'm just saying they have no roof (they are like DBZ, a runaway power leveling setup trying to one up the last flamboyant thing the characters did, constantly raising the requirement, defined as levels/ranks, of the characters to be able to beat increasingly, one after the other, stronger enemies) and the only thing still remotely ninja are the the concepts that a few of their "skills" are built off of, the outfits, and a handful of weapons. Not saying you can't enjoy the series for what it is, but that the series is not a "portrayal, realistic or romanticized, of ninjas", just a re-envisioning of the basic concepts exaggerated to ridiculously massive proportions. It's as much about ninjas as DBZ (the entirety) is about martial artists. If you want to buy cheap DFO gold, you can go to ssegold.com.

Though maybe it'll be easier to have someone explain how they view ninja and how Naruto lines up with it. It is really hard, but if you try, you may succeed. In terms of my experience, it takes three weeks or so to get full level. Or you can buy DFO gold to get fast mounts and good armor.

Edit: Oh, and Ninjas assassinate people, they do not go about acting as symbols of justice saving the weak and helpless from the wicked. They do not get to choose what they do if they have moral objections to the act, the ones who choose the morality of the actions are their masters or their village.