I’m not sure what “at the time of the initial trade” matters at this point? The same 1.5 years have passed for both Burger and Eder. Eder has pretty much busted and Burger has continued to hit some dongs in the majors without any defense.
The Marlins got back the Rangers #17 ranked prospect, plus two additional prospects, for Burger. Meanwhile, Eder is currently the White Sox #22 ranked prospect.