I usually lurk in trade almost every day, and I see that the some players are already bored of the island. So I thought with some smaller changes could help these people. The idea is not about "give us more free stuff", but to get interested in playing every day. Some rethinking and balancing is needed.
Just like alliance tasks, there could be Island tasks, and completing these would give the boxes a minor box boost, just like the premium boxes, only weaker/ different ones. Tasks could be: kill a given amount of infected/ HERC soldiers; eliminate all HERC soldiers on a map; disarm a given amount of mines, survive rushes, loot containers, finish all maps under 20 minutes etc. These task could turn up every day, or randomly 2-3 times a week. Also, there is an alternative prize in my head: instead of a box boost, we could get a badge for our leader, with a small boost, like +aps, move speed, less injury chance, etc. Every week with a different boost, and with gold, silver and bronze quality.
I hope you like my idea.