Neither Slackbuilds.org nor src2pkg are official Slackware tools. They also don't make packages in the same manner Slackware makes packages.
To be honest, I've found Alien Bob's
packages to be better built than Slackbuilds.org packages. I prefer the way he makes his packages.
Allowing a forum/sub-forum for them would open the door for other unofficial tools ... such as swaret, slapt-get, etc. This seems like a bad idea.
Slackbuilds.org has an IRC channel where you can go to discuss issues with their packages, the contact information for the package builder is in their scripts and on their website, as well as the mailing list you mentioned. It seems like joining their specific mailing list "would be more convenient for people who are limited in the time they can participate in Slackware activities."
What you run into with Slackbuilds.org is many different people making and submitting packages, all with different ideas about how to build, what permissions to give directories, what to put into packages, etc. With Slackware they all fit into Pat's package scripts and we know what they do. With Alien Bob's packages, there's still just the one guy building the packages, so you have consistency there, also. I prefer this system of one guy with the final say, rather than the Debian type of democratic system where many people make final approvals.
Just my 2 jiao.