I do not know exactly how the bot report system works. I do have some knowledge of how the spam system works, though. (I help with the Dreamwidth antispam team, and our spam system there was originally copied from LJ's, though it is possible that they have different settings, or have changed things since we forked off; I know we've changed a few things.) In the comment and entry spam system that I work with at Dreamwidth, which is at least similar, one spam comment or entry deleted by someone is enough to put in a report.

I think it is likely to be slow anyway, but I also think that making a centralized list would not be helpful. There's nothing that I can think of about the bots on the latest page that makes them any better or worse than any other one out there; if they're really vigorously spamming up the latest page, and people are watching it, then they're going to eventually wind up with more reports anyway. I know I've seen multiple entries from the same account in one page, and I have no reason to believe that they're going to stop blasting out entries, so they'll probably have entries there when someone else loads it.

And yeah, I hear you on the new-account-creation front. I suspect everyone dealing with spammers is discouraged by that part.