Therefore, I ask, what would the forum be like without signature campaigns?
Would it be more sanitized?
I do think that it will be more sanitized in a way that you will be seeing less posts with spams. Since there are no campaign signatures present, the discussion would involve about a certain topic whereby only the people who engage in such discussion would reply.
Would it be less filled
with spams?
Definitely- there will be no reason for any other user to spam messages in this forum in order to meet their weekly quota of posts. With less spam on the forum, this will make it more or less sanitized, in connection with your first question.
Would there be fewer alternate accounts?
I do think that there will also be fewer accounts. There will be less merit for a person to create multiple accounts since majority of newbies create different accounts in order to participate them in different signatures.
Though this may be the case, I do think that campaign signatures are an integral part of this forum in making it more active. Since this is consider the biggest and largest cryptocurrency discussion platform, lots of businesses are taking advantage of this traffic for advertisements.