This what you suggest (reducing the witness votes) is one out of two possibilities I see.
The second one is to allow accumulation of witness votes, means that you can vote for 30 witnesses and every witness receive 1 vote or only for 1 witness and he receive 30 votes, or something between.
I wrote a post about this (let's say I wrote in german and translated the post):
If you want you want share your opinion with me.