Team loyalty is an important factor for team management and by effect player's user experience.

Reward the team loyalty and contribution can help to suppress tensions and discords due to team management (inactivity, leeching, leaving for another team race or all others uhealthy opportunities...)

Two additionals "war chests" (defense and attack) would be gain by players that perfectly contribute to war (5 attacks to get "attack war chest" and keeping 15 war tokens while already gaining "attack war chest" to get "defense war chest")

Theses chests should be "10 steps chest".
Best rewards should append after 10 perfect wars but reset to first step when missing.