This is only a meaningful question if you are abitrarily assigning a reputation value to an action, which feels sub-optimal.
If that is the case, then absolute values seems like the better of the two options, as a relative percentage would effectively introduce an inflation rate on reputation that is determined by the rate at which the associated action takes place.
I tend to think that including both is the optimal state, as they provide different contexts.
Decay over time helps ensure that one’s reputation is relevant to the current context in time. To steal your own example form the DGOV channel, it probably wouldn’t feel right if someone who earned a ton of reputation 10 years ago, and subsiquently hase been univolved, showed and threw the weight of that old reputation around.
Inflation gives context to the raltive size of one’s past contributions given the current state of the organisation, regardless of when those contribution happened.
I personally like the idea of deriving reputation from a stable coin or stable value to ensure the relative magnitutde of reputation awards remains somewhat consistent over time.