salaam Bassam,
Seeing that interpretations of the Qur'an can differ and one can't clearly show the other to be wrong, the central theme of Quran Onlyism fails.
Traditional Muslims recognize that not all of scripture is literally 100% clear, while Qur'anists make it appear as if that is the case.
Is differences of opinion are possible, then isn't that a tacit admission that not all of the Qur'an is clear?
It seems to me you are claiming things about the "Quran-centric" position that are not true.
Please clarify, are you implying:
1) Those who advocate "Quran-centric" or "Quran-only" claim 100% of Quran is clear and there is only one interpretation possible for every verse?
If so, please state who said this, with link. Thanks.
2) Are you aware of verses such as 3:7, 3:159, 39:18, 42:38 and 58:11?
If so, can you tell us if they allow for the possibility of variance of opinion with regards to dealing with matters. Yes/No/Unsure.