I believe that some tasks here that Sebi is doing by himself are likely better done with by a small group of people.
If there was a way for a small group to help address trade disputes and help with any small tasks on the forum (moderation, answering questions, writing up decent feature requests and bug reports) that would probably help free up Sebi's time to address other things that are harder to delegate.
It also seems like there should be a way to train a small group of people to add cards to the system, as long as there are some steps laid out, it seems like others could help here. Maybe it isn't a huge task currently (like 2 to 5 hours every few months), but having others that are trained to do this could dramatically help the site be more complete and completely usable instead of having to make notes about adjustments to make when the cards are finally loaded. Just being current could help get people using the system or retain people that might end up going to other solutions.
This isn't taking into account the features that could be added to the site, where it may be more difficult to add people. I think that adding others to help with the more mundane tasks could help give Sebi time for those aspects.