SE did this in FFXI for delve. Delve was the main alliance end game event for the Seekers expansion. Each zone had 5 bosses and 1 mega boss they all had their own drops but once you beat a boss you would get a key item that would make a NPC sell the items that the bosses dropped. Now everything you killed in delve gave you points to buy stuff. However you only needed to kill everything once to unlock all the items on the npc and pretty much buy everything. People were geared up with all the gear in the game like after 1 month.
Had they needed to keep farming bosses would of been much longer to gear up.
However bosses weren't exactly push overs so people who could clear the stuff easy started charging 20m to carry people. People wanted the key item so they just needed to kill the bosses once so then they paid LSs 20m for runs through the zone. Then to get their points they would just farm trash mobs over and over to earn their points because they weren't good enough to do bosses.
I think it was a bit silly to have all the best gear in the game after like a month. Then you are sitting around for like a year waiting for SE to come out with new content.
