Iverson's point is more regarding semantics than syntax, though. The only mention of syntax suggests its better for it to be simple (presumably so that the semantics are closer to the surface). Every programming language is a notation for describing computation; notation is a catch all for all three levels: orthography, syntax, and semantics. APL is interesting because it not only uses an unconventional syntax, but also an unconventional orthography (obligate usage of special symbols), and its semantics are different as well from most languages (array programming). Iverson's point is that APL as a notation is valuable for making the structure of certain computations obvious, and that this point generalizes across programming languages.

GingerBill's article is making a narrower claim: that semantics are what determines a good notation usually, not syntax.