Developers should play this to see what NOT to do.
But before I tell you why, I should mention that if you are a fan of the anime, the kind that never misses an episode or manga volume, then you may find this game worth playing, but definately rent it first to make sure you like it.
For the rest of us, who occasionally watch the anime on TV, reads the occasional Shonen Jump adventures, or are just looking for a new fighting game, this is NOT your cup of tea.
The main issue with Ultimate Ninja 3 that gets me is how incredibly unbalanced the various characters (and there are a lot of them, by the way) seem to be. The combat is dumbed down to the extreme (which is why fighting game fans will not enjoy it). You press one button to attack, spam it to combo, or combine it with double-taps of the directional buttons to do random combos or special moves. The thing is, some characters' double-tap combos are insanely powerful, taking off large chunks of the opponent's life, whereas other characters can only hope to do that much damage by pulling off an Ultimate Jutsu.
Speaking of Ultimate Jutsus, you'd think that a move so powerful would require a certain combo or certain circumstances to pull off--but, alas, that is not the case. To perform these half-a-life-bar-of-damaga-dealing moves, you need only press Triangle, then hit your opponent with a single regular attack. You CAN avoid most of the damage here during the button-pressing thing you get, but that particular thing (I dunno what to call it) is very poorly designed, giving you entirely random combinations for each player (meaning one player could essentially get the same button six times in a row and pretty much win by default). To make matters worse, once you're UJ is finished, you will have a chance to transform into various levels of "Curse Mode". For some characters, this could mean a virtual instant win, because he/she will become so extraordinarily overpowered, but for other characters, it could mean a loss, because you become very powerful but very slow-moving.
You can also use items in the midst of battle, and you have unlimited shuriken to throw. However, you need to press R1/L1 to cycle items, so you will often find yourself relying soley on shuriken as your item of choice, simply because taking the time to cycle to the item you want and use it (which will involve paying close attention to the corner of the screen since the HUD for items is so tiny) could mean a large life-loss or even death.
Ring-outs are also incredibly easy to pull off--thank your lord that they don't mean instant loss. In one particular match between my friend and me, he was using a character whose regular attack had a range equal to the entire arena, was multi-hitting, and had an enormous push-back effect, even if the recipient is blocking. So, he knocked me out of the ring, then all he had to do was use his regular attack over and over, knocking me out of the ring over and over, and there was absolutely nothing I could do about it.
So, all in all, I did not enjoy my experience with this game at all, but if you're a hardcore fan, then it might be worth checking out.
Cheers, all.