Gradual extinction delegate votes on each next voting

[chiliec]

I want to propose to change vote for delegates — most fresh vote gives to delegate more than previous.
For example, last vote equal to power multiply 1, previous multiply 0.9, previous * 0.8...
If delegatee lived up expectations again — user can revote for him and give him most power.
In this way we don't need to complete clear votes because delegates which aren't showing activity will receive less and less weight at each next vote and eventually fall out of the top.
What do you think guys?