The disadvantage to this approach is that doesn't require the user to re-consider their votes, they just click a button and all votes are renewed until the next cycle. While it's certainly easier from the perspective of user-experience it doesn't promote thoughtful engagement.

Consider that in Western democratic elections your pre-existing votes don't stand from election to election. As an individual you have to explicitly recast your ballot. This forces you to at least consider the other options available to you and if your last choice really remains appropriate going forward.

In the end, what needs to be achieved is the relinquishing of the stranglehold that a few select early adopters have on the evolution of the Bitshares system and while voter decay doesn't guarantee this, it does provide the two fold benefits of filtering inactive stake and forcing those remaining active users who delegate or vote with their stake, to take into consideration what they are voting for or whom they are delegating to.