If everything is in a closed box, then there is no worry about economy, so this is good.
However, a few concerns:
1) Some people like to semi-AFK-craft (just hit enter and not pay attention). What would be the incentive to start paying attention. I.e.: Significant XP gain versus doing on your own?
2) It may need to be a higher level gap or it would be hard to find people? As well as perhaps not restrict to 8 only. I would think 2-8 would be nice, with a bonus for more people. And XP gained should be scaled down individually.

This could be based on realism:
A small cottage-industry with 2-3 people making shoes, or a full scale restaurant with 8 people working busily.
In both industries there could be the master artisan (who would perhaps be level 45) as well as some journeymen (level 30) and apprenteices (level 10).

I can visualize it thusly:
An instance created. A small mill on the edge of a river. The DoL go out and gather some materials from the forest on the edge and bring it back to the mill. The carpenter puts it in the mill and makes some planks of wood. This is then given to the smith who makes a hatchet out of it. This is then deposited into a box and converted into points for everyone.

Content can scale based on level and quantity of people. There be no need for other rewards. But it COULD lead itself to a 'Shop Defense' mini-game in the future where there is a time limit and a certain number of items have to be made for customers before they get angry.

Yes, I see great potential ^.^. And me spending much time in such an activity.