The success of the proposal depends on how many people change their behaviour. Many of the account holders with significant SP are supporting the changes. So we should expect these people to more actively curate content. Several people previously curated content and switched to vote selling because their earnings were significantly falling behind the people that sold votes from the very beginning. 25% curation rewards is far less than 80%+ from vote selling. The bots use an SP maximising vote strategy of 10 full votes a day. This reduces the value of all upvotes, which further reduces returns from curating content.
Ultimately, it goes back to my first statement regarding changing behaviour. If we assume the EIP does not increase the price of Steem, authors will need to earn 50% higher per post to cover the increased curation rewards. So we would need quite a few people to change their behaviour for authors to be better off.