I still dont understand how using a subtractive effective SP makes it rate limiting...
It only reduces the power for upvoting someone with a lot of SP, even if the subtractive factor is sqrt(SP author) it biases upvoting to the smaller SP authors.
There can be a million sybil accounts, but what does that gain? The whales have to vote for them and if a whale is voting for newbie accounts that he controls, this will be noticed wouldnt it? especially if the content is weak. So then he needs to hire writers to create useful content, in which case it creates useful content
Maybe I wasnt clear that this was just to reduce upvote power and not to increase it, so whatever attack you say it has, the existing system can be attacked the same way with more power