Are you sure about that? The math shows that with a set group of 18 people, going every day, you're going to finish one relic per month. It's still going to be a small fraction of players...
With the proposed numbers, its one month per relic per person. So if you and your 5 friends all have 1 relic, thats 6 months to push them all to 99. If you have 2 relics, and your 5 friends all have 1 relic each, thats 7 months to push them all to 99.
20 killshots is still somewhat annoying because you STILL need to have an alliance capable of killing ADL. Despite being lv90 content, theres still a chance to wipe at 99 fully prepared, so you cant exactly go at it with 18 melee looking to upgrade weapons.
To quell the rage, they're going to have to either:
a-Make it kills, not item turn-in
b-make Umbral Marrow / Mulcibar's Scoria drop from additional sources based on difficulty:
Arch Dynamis City boss: 1 Marrow
Arch Mainyu / Arch CC/Antaeus/AB: 3 marrow
Arch Diabolos: 5 marrow
Arch DL: 8 marrow
Tinnin/Sarameya/Khimaira(I forget the name haha): 1 Mulcibar
PW: 5 Mulcibar