This is all very well. However, an argument can be based on sound principles and be can be totally supportable, and yet due to limited speaking or writing abilities of the adherent, not be convincing. Of course the other is also true, a good writer or speaker can successfully convince a reader or listener of a totally false premise.
I see several skills necessary to successfully and accurately lay out a position. They are:
1. Ability to write or speak 2. Depth of knowledge about the subject 3. Ability to listen to or read material and understand it to a depth beyond the superficial. 4. Ability to analyse--this implies an IQ at least as high as the speaker or writer. 5, Access to additional material pertinent to the subject 6. A world view relatively free from preconceived notions of reality.
I am reminded that when I have arguments about politics, conservative versis liberal; ie which is a better philosophy--the question has to be asked, compared to what, for what purpose, etc. The argument to me can have no resolution.