IO540 - I also think you are reading too much into this. The text you quote is NOT about validation and conversion of licences; it all hinges on whether EASA considers a licence to be "acceptable". I interpret that to mean that EASA is reserving the right to claim that, for example, a licence from darkest nowhere-land is not acceptable. If you simply substitute "USA" for all the legal-speak "third country" verbiage, you end up with (paraphrasing a bit):
"The requirement for a licence may be satisfied by the acceptance of a licence issued by the USA for pilots involved in the operation of a US registered aircraft".
At which point, it looks like the current status quo.