The problems in real world politics are too numerous to go into. haha

I like both your ideas.

• Being able to vote for 30 allows a few huge accounts to control all top 20 witnesses. Limiting the number they can vote for would certainly be a step in the right direction. At least then, the majority of users might actually have a say in the other witnesses. That is needed.
• I also like your idea of vote decay. Some of the scenarios you tossed out could already have happened. (A whale moves on and his witness vote lasts forever...)Here in the states, we tend to vote back in most incumbents. Once politicians get elected, it seems near impossible to replace them.