It just means that the Uchia, people who killed their best friends and ripped the eyes out of their brothers' sockets, found the jutsu to be taboo.

You still need a sharingan to pull it off. And someone else COULD use it lol, Danzo.

ohhhhhh, loool stupiditty speaking on my part haha,

Hmmmm. I see your point.

I hereby deem Izanagi "The other Susanoo"

I would'a been like, I dream Sasuke is a whiney little bitch and only uses his own power.

or i dream the air sasuke is breathing is pure carbon monoxide

Or Itachi had killed him during the Uchiha massacre.

na then what would we have naruto to bitch about for chapter after chapter

that just blew my mind

Yeah, I hate how in the naruto world there are so many people with cheap abilities that could've wreaked havoc by now.

Honestly, too many abilities. How could 'replications' be a low level ability?
And how come they're easily sensed by high level ninja? On what basis can they measure whether the said ninja is a replacement or not, eh?

They just happen to know conveniently, yes.
I wish Masashi Kishimoto thought things through before giving people all kinds of epic skills.