I think it would be cool to have a achievement point npc who acts like a rep vendor.
This way achievement points would act like rep towards the entire game, and it would feel really nice to be getting closer to the next goal no matter what you do.
Even if it’s just a “explore zone” spot that you missed and gain 10 points, still feels nice to get 10 points closer to the next tier of rewards, something to look forward to.
40k is the cap now, so how about every 5k you get to unlock 1 of the 8 tiers?
Each tier unlocks pets, toys, mounts, full transmog sets and maybe some unique bop crafting recipes that have mats requirements from each expansion, so you need to do a couple vanilla, tbc, wrath, etc raids to get the mats. Tailor/LW/BS would have transmog gear, JC/alch/scribe/engineering/enchanting could have toys, pets, mounts.
Also, scrolls with unique titles are on the table.
Once unlocked, you can choose to pay for the rewards in honor points, marks of honor, or gold.
This would be a huge draw to maintain retention, and we all know you like to buff those numbers Blizz so how about it?