Agreed with @Rumaki idea in general. Agree with @Niticomment too, there are some silvers that don't stand out at all. @Ueda has already considered this which is great. Its something that should be evaluated very carefully by the team I think.
To me @Shiroubeats me in "achievements" or such as he was Kage and Akatsuki member before my time and spend a long time in these positions. Regardless of me being chunin before him.
1st Jonin in the World, 5th Kazekage, Chunin during Beta. These are my humble achievements in Nin-Online. Those titles can't be ever achieved by anyone else again. I've been part of the akatsuki, puppet brigade, ANBU in one point as well. The titles I have achieved are great, but times were alot different back then.
It is extremely tall task to compare who deserves NPCs and who doesn't.
I wish for the developer team to reach out to their players and ask what are their achievements, take an average out of their achievements and decide based on that which npc they deserve or if they do at all. For example I'd say I'm not cut for an Akatsuki NPC just because I happened to be a member after the first roster.