Suggestion is good, but ppl would rush the whole quest in the very 1st week or even first 3 days leaving the rest of the month same as now.
I would instead put a weekly quest who asks for 30 or 40 kills and give a token as a reward. We would spend this token for stuff at a specific npc.
Reward may be idians, medals (ceramium/BM), bag of lvl 60 compos, augment lvl2, 100% sockets and even non-tradeable tempering.
Ofc with different prices, taking temperings as example it would cost 4 tokens which means 1 TS/month