12.1 makes an attempt to reintroduce the battle fatigue / dampening mechanics to open world War Mode World PVP, with the Spectral Arena debuff (https://www.wowhead.com/ptr/spell=1304852/spectral-arena) that is active in portions of the Coiled Isle (note that this includes areas where War Supply Crates land).
This doesn’t seem very desirable for open world War Mode World PVP encounters. Those mechanics are arguably necessary for instanced arena PVP to prevent certain matches from stalemating indefinitely, but that is not the case for World PVP, when the parties involved can go elsewhere if things are a clear stalemate. That option is not available in instanced PVP which necessitates less natural ways to address that problem.
This reintroduction of battle fatigue/dampening effects in open world War Mode PVP seems to be in direct, stark contradiction to the stated design goals 12.1 with regard to reducing bursty/spiky effects in the game:
For reference, the aura currently has these effects at the time of this writing:
Apply Aura: Mod Healing Taken - % (Arcane, Fire, Frost, Holy, Nature, Physical, Shadow) : Value: -50%
Apply Aura: Mod Damage Done % (Arcane, Fire, Frost, Holy, Nature, Physical, Shadow) : Value: 25%