User blog comment:FinalFlash18/Kite's Power Level/@comment-14902757-20140618042751/@comment-23822532-20140618054134

Specialist is something that doesn't fit in any other Nen type, so it's plausible there are even unknown Nen types amogn specialists. But, from what we've seen, Specialists both are proficent in Manipulation and Conjuring (Chrollo and Neon can do this), but aside of this, their Abilities have unique powers and not something you can easily have through normal meanings, it truly is something "Special". For example, you can Conjure the deadliest weapon, Manipulate nature at your will, Enhance your fists so you can split the earth apart, Transmute your aura and body in an invencible sustance, and or Emit the biggest blast of Aura, but can you read the future? Steal someone's else Ability? Grant wishes (this is someone in the next arc does but I won't spoil it, just in case)? Nope, and whereas this might look like someone can pull off such abilities depending on the context they're rised and what they go through, how do you explain Komugi? Her Ability literally is getting better at Gungi, and basically being unbeatable, does someone with a Enhancer Nen-type can do that? Or Transmute their Aura in something they make them better at Gungi? No, that's literally impossible, so only Komugi can do that.

Therefore, it means that the difference between Specialists and other types it's the type of Ability they can have, their power is way more diverse and not many people will ever have something like that. For example, Pitou, an Specialist, can Conjure a flawless -in terms of result- healing Ability, but can also Conjure something that lets him MANIPULATE many people at once. And finally, Terpsichora, even though it is Conjured, it serves as an Enhancing Ability with conditions and rules which makes him even more stronger than your regular Enhancer -remember that Specialists, raw strenght-wise, are the weakest-.

That's what being a Specialist means: your Abilities and talent are nowhere close to anyone's, and it's plausible nobody can imitate it or make something remotely similar.