Actually recent versions of Illustrator *can* create Level 2 EPS. As can be seen from the screenshot below, Illustrator 17 by default writes Level 2 EPS (I have also selected "Illustrator 3 EPS" for better compatibility with *Mathematica*'s importer):

[![screenshot][1]][1]

I have successfully imported EPS generated this way into *Mathematica*. But in general it is better to save as PDF for this purpose.

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Also you can use Poppler for converting Level 3 files to Level 2 as I show in [this][2] answer.


 [1]: https://i.sstatic.net/62TJB.png
 [2]: http://superuser.com/a/650524/71768