The forum won't be better if signature campaign get banned, why?
No one cares with reputation, most of users scared of getting negative feedback, it will make them not qualified to join a campaign. So I won't be surprised to see every users will have negative feedback due to disagreement or not being nice.
You will see merit abuse, trust list abuse, trolling etc in everywhere.
And I will probably join one myself if I get a chance one day

you didn't even apply a campaign.
There are two campaigns that accept Member rank and still open for new participants.
Thanks for informing me about this but I am in no rush to join a signature campaign, and if I gonna apply it should be something I can back up proudly and of course the campaign also need to want me to using them.