What I have heard, which might well be inaccurate, is that the EU tried to sign up a bilateral treaty with the USA, covering a wide range of issues.
Some of these were trivial and some (like EU airlines being able to operate domestically in the USA) were not so trivial. The bilateral license acceptance bit was thrown into the pot.
Last I heard was that the FAA walked away from this, and shortly afterwards EASA brought out their latest proposal which subjects ME turboprops and jets (but nothing below that level) to EASA maintenance oversight. So Socata and Pilatus are in, but King Airs are out (and will have more hassle) because they are, along with most jets, American.
It's all a bit dirty.