Hi Justine,
30 votes rule is as bad as what exchanges have done using customers funds without consent, and take over was possible due to 30 votes rule.
I have asked about 10 witnesses for a comment - none did. Very telling!
https://steempeak.com/palnet/@hotbit/steem-blockchain-multivote-security-vulnerability
Considering that 11 witnesses in the to 20 are enough for a super majority having 30 votes was a mistake. But since @justinsunsteemit has tasted the power of the twenty sock puppets I don't think this problem will ever be addressed.
Instead I fear that @justinsunsteemit will power up until he has full controls over the blockchain again.
17/20 is a super majority.
The only way to address the sock puppet problem is to apply a non-linear convergent curve like in EIP to witness votes. That will force a Sybil attacker to pay a higher price or group his sock puppets behind the same proxy (a proxy should be calculated as one vote for the purposes of calculating the curve tax), which allows for the sock puppets to be recognized as representing the same entity.
Yes, limiting power with a sub-linear convergent curve would have been best. But up until now most Steemians have rejected the idea.