People who understand the manga would tell you that out of the three ninja art's genjutsu is the superior. Backed by the fact that not many ninja's specialise in it, it can be lethal when used properly and im not talking about ms genjutsu or any of the op genjutsu, but simply genjutsu.
I keep on hearing people saying so and so character cannot be trapped in a genjutsu and every time i see such comment i facepalm, because they relate this to what happened with naruto and itachi., The reason why naruto was trapped is because he cannot break it, but also the reason why he lived is because itachi didnt attack him whilst naruto was in the illusion. He couldve 1 shotted him, no different to what he did to oro, but also the scenario with deidora.
Genjutsu in general is not about trapping your opponent and majority of high level ninja's know how to dispel genjutsu, that is if they know are in one. Genjutsu is to create an opening, a vulnerability for the briefest of moments and to use this illusion to your advantage. If you really want to know the power of genjutsu, look at how sasuke used it against danzo. That imo was one of the best ways to use genjutsu in the series and as tobi said it was a weak genjutsu, but you see thats all thats needed to fool an opponent, create an opening.
