Jeremy K. said,
What I would suggest is a way to update a tokens stats across the entire campaign so that every addition of the same token has the same stats.
Since character sheets are going to be implemented soon, they can incidentally address your petition: they will allow to link tokens to them, most likely being helpful for keeping character consistency between any Roll20 elements (pages, maps, whatever), across the entire campaign.
I mean that perhaps any change in the stats of the character sheet can be automatically updated for its corresponding token, if it has any (I mean, stats for things to be tracked very often, like Health, Fatigue, Magic, etc), regardless of its current place in the Roll20 app & campaign.
So, instead of adding stats to tokens in maps, a different approach could be just creating characters, and if it's suitable, assigning tokens to them, with character sheets being the "central tool".