We recently added scoreDetails to $rankFusion and $scoreFusion. Both of those stages can accept $geoNear stages in their input pipelines (along with a combination of other stages such as $score). 

For ex:

scorePipe1: [ {$geoNear: {near: [20, 40]}}, {$score: {score: {$meta: "geoNearDistance"}}} ]

It could be useful to set scoreDetails metadata for $geoNear such that users who use $geoNear as inputs to their hybrid search pipelines can see/access the relevant info that went into calculating metadata fields like "geoNearDistance"