If this forum does allow mixers again then a problem needs to be addressed:

How do we stop mixers coming to the forum, running large budget signature campaigns and running off with the loot when the reserve becomes large enough?

I don't think the forum should allow mixers until there is some form of policy on how these mixers work. We need decentralized solutions, not centralized ones, if the forum wants to succeed with mixers and if users are to be safe. Bitcoin has evolved a lot since the ban, creating decentralized mixers can work, so I would hope that the community rally together to build a decentralized framework in comparison to relying on anonymous individuals who abuse the forum and its people.