I don't think that only working in 1v1 / team-v-team is a good reason to leave it disabled by default. Making it work for BOTH 2-teams and FFA would be a huge effort, moreso in the graphic design than in the coding. I don't think anyone will be put off by the spec panel not appearing during FFA, and I think everyone's experience will be improved by having the spec panels displayed when they're watching a game where they're applicable.
See https://zero-k.info/Forum/Post/175038#175038