Why do you call Shia Islam unsatisfactory? The Twelvers are Muslims, just like the other branches of Shia or Sunna. Pardon me if I'm mistaken, but I suspect that you don't like the Shia and therefore depict it as a heresy in your posts.
No, this is a historical reality. One in which Shi’i scholars themselves accept. I can present a multitude of sources for this. To the view that Shi’i Ulema themselves have specific traits and the Takfir that their Ulema make on others. Not to mention, the vast number of rebellions which various Shi’i waged against the Khilafah.
Regardless, Islam is irrelevant, religion does not work like you believe it does. The similarity of names does not mean a similarity in beliefs or a similar root does not mean a similar religion. If one was to say this, it would become extremely worrisome the Manichaean question in regards to Christianity.
Also, instead of assuming a dislike of Shi’i from myself, study deeply from its Ulema and read the history of its existence to find my assertions proven generally. Though, in the west, it is common for you to gloss over Islamic history and compare it simply to the religions you are familiar with, unfortunately this is becoming more and more common on this site.
As a disclaimer, there are 3-4 types of Shi’i generally, so not all fall under the category I am discussing. Heresy,,,, I am discussing history not whether I believe Shi’i are kafr or murtadeen (apostates). Simply the vast number of Shi’i revolts proves my point of deep distinction historically.
Also, where did I claim Shi’i to be unsatisfactory? I simply am making a distinction. Would it be me saying Christians are unsatisfactory if I made them distinct as a group against Manichaeans or Jews? In the religion of Islam, this distinction is essentially not needed.