Instead of a direct power up tax, I think an indirect power up tax should be considered. For instance, newly powered up Hive does not collect from the tax pool for say 90 days, or some length of time that everyone agrees on or that is a witness setting. It benefits current Hive Power holders because the tax that would have went to the new Hive power will go to them instead, which is basically the power up tax in reverse. The pain is not felt at the power up though so it doesn't seem as bad to me.