Totally agree. Fees adjusted to voting power are absolutely necessary.
IMO the best way with voting is to make the fee for the vote proportional to the stake.
What fee? 
If transaction fee then stakeholders would return them by forging own transactions in own blocks.
If fee to some voting address with somewhat redistribution after voting then it is gamed again by creating many accounts.
As I already pointed out: splitting (because having more accounts is better) and merging (because one huge account is better) is a good thing. Because, you have to pay fees for it. And if even only 5% of these fees will drain out from the whales, it drains out.
So, a good thing. Distribution is what makes Nxt strong.
**Edit:***
And yes, I would recommend even distribution among all voters to have an antagonist to forging.