Sounds a great idea and fun.
But I would like a split up with mob size and number of player need. Cause I feel like this way is more fun. You know when you have like a bunch of player to hunt with you and you target just small as a rabbit. It would kind of turn you off right? Or a super big nm and you kill it with only 8ppl. It would be boring also right? "Hunt" is suppose to exictment and fun and Tactical right>?

Example:
A small large size NM with 3 player to kill it.
Place: Anywhere.

A Medium large size NM with 8 player to kill it.
Place: A outdoor area with some space

A Big large size NM with 16 player to kill it.
Place: A cave or castle.

A Extra large size NM with 32-36 player.
Place: dungeon or top of moutain or castle or like ffxi bcnm/dynamis area.
Apply only 3-5 linkshell with larger member each week and the linkshell who win/lose from lasttime can't join the after next week. Of course add a List call freelancer for those player who have interesting to join but dont have such larger linkshell or the linkshell dont have enough people.(With this way lonelywolf can join battle at sametime can play with new player)

Just my silly personal idea feel free to ignore it.