The efficiency gap as a formula isn’t particularly of note, what won the Wisconsin case was the approximately ~70 pages of further statistical analysis that Simon Jackman performed (available here).
The UK has a pretty poor efficiency gap despite having a truly independent boundary commission. Voting distribution doesn’t sync neatly with population and spatial distribution and an efficiency gap itself is not evidence of gerrymandering.
Efficiency gaps are a hallmark of single member first-past-the-post systems more than they are of gerrymandering (hence why Jackman’s research shows almost all districts to be ‘gerrymandered’).
Using a formula that breaks down in edge cases isn’t electoral reform, and electoral reform is the only thing that removes inefficiency and unfairness from the electoral system you guys use.