A much simpler idea is a weighted lottery distribution system. Leaders define the "worth" of activities members take part in. And when distributing packs then can click to randomize distribution. Those with more points will high a higher chance to gain a pack, but overall its still luck, so its fair.
Ex: Leading convoy 1 pt.
Assist in convoy .5 pt
Leading TI 1 pt.
Assist in TI .5 pt.
Lead Group Instance 1pt.
Assist in Group Instance .5 pt
Attend 1 round of GNW 2 pts.
Cheer 1 round of GNW 1 pts.
Gold donation 100k per pt. (Max 5 pts per week, prevents top players in ninetails from buying packs so to speak and everyone can spare 500k coins every week, and 500k coins is easily obtainable by a active player)
Leader Commodation +1 pt. (If you see a player go above and beyond for others, helping make teams, etc etc, Max 2 pts per group member)
I was debating on whether or not people have to have attended GNW at least 1 round to be eligible