I'm not trying to convince you specifically, just sharing my reasons for supporting this project in spite of the questions and concerns raised, so people who are just joining the conversation can see both sides and add their thoughts.
I see your point about more content bringing more visitors and, thus, more potential donors to the website. But, to be fair, the larger the website, the more servers and space they need to host it all. All that costs money. Since they can't charge us to use their site and don't allow ads like a lot of other free sites do, I personally don't mind them asking for donations periodically.
While copyright laws are murky when it comes to fanfiction, the concern about copyright infringement is valid. But I do think there is a difference between one of us posting another author's work somewhere else without their permission (which AO3 does not allow) and Chaos, as the owner of a dying fanfic archive, giving permission for the archive to be moved to a more functional platform in order to keep it up and running. He's taken on the responsibility of maintaining this archive, but, because the eFiction script is outdated and no longer being supported, that has become more and more challenging. He made it clear a few years ago, after frequent outages lasting several days, that it's only a matter of time before a server update or something else kills this site. Thankfully, it's lasted longer than a lot of us thought it would, but it's not going to last forever and is barely functional as is. Transferring it somewhere that will allow authors to actually update their stories and interact with their readers again makes sense. While it's true that AO3 has lengthier, more detailed terms of service than AC, its platform is similar, and its purpose is the same.
That being said, I completely agree with you that we should care about an author's ability to choose what happens to their work before it's already happened. I don't think I would support this move if it meant giving up control of our work. Creator control is important. That's why Chaos came here to ask for our blessing two months ago before moving forward with this, why he's asking our opinions on the next decisions that need to be made, and why we, along with Open Doors, will do our best to spread the word about this once we have a better idea of when the import might actually begin, so authors are made aware of their options before that time.
But, in the case of authors who may miss out on the notifications, I feel this is one of those times when it's better to ask for forgiveness than permission. If they find their work on AO3 after the fact and are upset about it, that's an easy fix. It's harder to get back the work that disappears when a site goes down for good. I can almost guarantee there will be others who are grateful that their work was saved when that inevitably happens to AC, and, for me, that outweighs the risk of pissing people off. We'll have to agree to disagree on that part. Either way, I respect your opinion.