There should be 2 exchanges
1) 10 earrings of the same type, to get an earring of the same type of a higher tier
2) 3 earrings of any type, to get a specific (your choice) earring of the same tier
There, fixed the earring system!
Each time you get a new one there's a new "roll" on the stats of course, so you can keep tryin getting the same +2 until you get the stats you want (max?)
Close but that's too inventory intensive unless you can store the earrings at an npc.
Probably should be X cases for a case +1 and Y case +1 for case +2
Or 4 (same) <job> earrings for a tier up for 3 (mixed) <job> earrings or 2 (same) <job> earrings for different earring of the same tier.
X= 30, Y= 10 maybe?
Cases can (and should) be a larger number if doing exchanges since they stack and also yield the same random chances, this works out to be 300 cases to get a +2 from all NQ, or 600 (worst case) for the job you want. If you can sacrifice some inventory I think it'd be a bit faster if you're lucky. (still painful but better than we have now!)
Not that it matters, as said system probably won't be implemented. The dev team is Keith Moon and we're a hotel room at this point.