I have no special inside information, but like other organizations, I have seen FamilySearch eliminate reporting of personally identifiable information in some cases. We can speculate the reason, but that has no bearing on this discussion. Lack of details makes it more difficult to track an activity like you have, but it also prevents individuals from being singled out (both positive and negative details). Getting members to self-report may be difficult, but I think it's the only way you will get the information you want. However, any comparison could end up doing more harm than good. If someone is discouraged because they are not in a position to do more than what is reported, the reporting may have the opposite effect you want.
A few years ago in another ward, we did an exercise with the youth and asked them to self report their indexing results as the campaign progressed. We reported the percentage of YM and percentage of YW who were indexing along with the total records indexed (by total youth, not by YM or YW). The goal was to meet a set number of records indexed before the end of the year (I was tracking it and posting a graph tracking the results on a bulletin board in the church - we had to re-set the goal several times during the year as the youth kept pushing past it, LOL) The campaign was to increase participation and interest in indexing, not to see which group did the most (which is highly depending on the projects available, the technical difficulty of the projects, and the skill of those indexing).