I am using PP on wotlk classic and the cpu usage (not memory) of pallypower apears to be way higher than of all my other add ons.
in a 40 man raid it is using 33+ ms / s

Try editing PallyPower.lua, find
self.buttonUpdate = self:ScheduleRepeatingTimer(self.ButtonsUpdate, 1, self)
and change 1 to 10 to rescan players less often

Thx that will probably do it for now :)

But I guess a good solution for this would be to actually hook all the nassesarry events instead of having a constant update truth a timer

There's one event that scans classes and updates every button