Strange, I always thought players in top guilds wanted to top the meters and are naturally competitive and self reliant when it comes to min maxing. If they don't because it is a small gain then apparently that is the playing field of your guild. Now then lets say you as management want to keep this high. But since time is limited and if people do not see the need for this (compared to other min maxing), or value of it (idem), then who are you to complain?
Other people have summed up your options already: track the valor buff (not water proof due to alts), track the VP achievement (assuming it is character only) or tracking armories to see if they upgraded their items.
If you have issues getting VP cap doing daily challenge mode is both fun as well as competitive and doesn't take too long. Getting an in progress LFR with a bunch of healers should also be pretty quick, and zerging through a daily HC as well.