thats called a cancel lock (i think) alot of people can do it not only itachi. you wont be able to do anything for like 1 or 2 seconds. many people do this and finish it with ougis, not just itachi users
And yeah I know alot of people can do it, but that doesn't make them cheap because alot of the time to have to combo juggle your opponent. And can be kawarimi'd out of almost at any time.
In Itachi's case all you need is a* throw. One chance to Kawarimi, you missed it and you're as good as dead. Also he lock lead straight into Tsukiyumi(Damn I reall need to learn to spell that)* and again, that has many possiblities.
So while other characters have button locks too, its Itachi's easy button lock method, blazing lv2ougi startup, Tsukiyumi, fast exploding bunshin, quick ground throw, near infinite air throw, really good -> + O attack which makes him cheap.
sasuke and Kakashi lol this is what i do when i play against my brothers first I wait to see who they pick so i can [see if i can copy their moves] then i pick kakashi or sasuke so. Then i use one of there special moves that usees sharingan. Once i see sasuke or kakashi uses the sharingan in there cutscenes i stop and do nothing when its done i just.I just finish my brother off with there own fighting style and jutsu