@fyrst-witness, I like your idea of taking the average voting power when undelegating but do you have a way to prevent things like this? You could use your entire account’s 5-day voting power by voting for one post repeatedly just by transferring the SP to a bunch of accounts that you don’t use. Maybe we could also have something in the code saying that the same SP can't vote for the same post twice, regardless of which account has the SP?
Or maybe another solution would be to allow instant undelegation at any time after 1 full pay period has passed? So, as long as it has been delegated for at least a week, you can undelegate instantly (voting power adjusted accordingly)
Can't really keep track of that, SP is just a unit getting moved around. what you can do is maybe add a "temp ban list" of posts to each one of the parties accounts with those urls so if one of the parties from say 100 accounts that got delegation from from 1 account voted while having delegated steempower the with the undelegation all accounts affected will not be allowed to vote on said post until payout. Problem is that this could be a huge loop to process so his method of correctly calculating voting averages still seems more realistic, and say the undelegated account has not used the delegation for a bit then you could get your delegation back at full power much sooner.