As someone who has worked with EpiPens for seven years now, administering them to patients weekly, if not more, it's very hard for me to find any claim of "improving the product" to be more than lip service. Certainly I don't consider the drug beyond active ingredient, but in the delivery mechanism (where they've also claimed "significant improvements and refinements", very little has changed. The shape of the container is a bit different, the 'window' to see the drug (to look for cloudiness or discoloration) is a little bigger (mind you, such a window is more akin to "empty space in product coloring and branding").
Certainly, I know some things might happen "behind the scenes". Maybe they found a more durable spring for the needle (not that was ever a problem), or such. But yes, I struggle to see it as anything more than patent extension.
Which is why, after our relatively small county, which THROWS OUT $100,000 of EpiPens a year in the Medic One system (which we are mandated to carry by state law) is moving to train EMTs to draw up epi from $2.80 vials, themselves.