Awesome. Do you have an ETA for implementation?
I don't. But I'm going to try to slip it in this month
Also, will there be a setting for a 'full value life' as we have now? For example, mojoman earned 25 DKP for a run and those points will remain at full value for 30 days, after which the tax will be applied.
There will not. The delayed decay can only apply to decay, because with decay each item/raid decays independently. Independent Decay allows for the analysis of decaying only events that are "old enough" because you can look at the date of each.
With the Tax, it looks at the total as a whole and simply does something like the following:
User X has 150 points, apply 10% tax, which is 15 points. User X now has 135 points.
Make sense?