Model parameters and performance measures are tightly coupled to the model development. Often, as models grow complex, data structures need to be changed, and their mappings to parameters, performance measures need to be updated.
Having to access three levels of windows to access the mapping of such structures is cumbersome and time-consuming. Having to three-click to access drop-down options is also frustrating and inefficient.
A simple one level table with progressive columns to be used (or left empty) would improve usability and allow for more visibility of the current mappings.

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In addition, the eyedropper option should be capable of mapping table values by their row/col numbers (or, even better, headers).
I hope this helps.