Making the case for Islam.

[ReptilianPeon]

Difference in opinions about the Quran is actually one of its essence:

Sura 3
( 7 )   It is He who has sent down to you, [O Muhammad], the Book; in it are verses [that are] precise - they are the foundation of the Book - and others unspecific. As for those in whose hearts is deviation [from truth], they will follow that of it which is unspecific, seeking discord and seeking an interpretation [suitable to them]. And no one knows its [true] interpretation except Allah. But those firm in knowledge say, "We believe in it. All [of it] is from our Lord." And no one will be reminded except those of understanding.

You can guess the role the Hadith plays in this. So now, using this verse, we can refute Sunni/Shia claims about the "unclear" verses.
But for example, a clear verse is the verse that says God is one. Why don't the "Umma" stick to such verse instead of fighting over an unclear verse?

"And no one knows its [true] interpretation except Allah."
That's the key. Allah realeases a complete commentary on the Quran and the conflict goes away. Not all disagreements come from the Hadith though. Desires also drive people; organizations and governments can manipulate religious texts - drive the agenda - especially if a large number of people are illiterate.

And I don't think the Ahmadiyya group (not aligned with Ibadi, Sunni nor Shia), of which there are millions around the world, justify their belief in Mirza Ghulam Ahmad solely on Hadith. Although, to be fair, the Quran doesn't have much to say about Madhi - as far as I'm aware. However, Ahmadiyya also refer to the Bible for their justifications of Mirza Ghulam Ahmad and say he is related to the second coming of Isa. They don't have their own collection of Hadith like Ibadis, Shia and Sunni do; they largely use Sunni Hadith.