A small change to the Thundering Affix in Dragonflight will help prevent the worse case scenarios when the affix procs!
The seasonal affix now provides root immunity and prevents slows from reducing you movement speed below 100% while you have the debuff! This should make it more consistent to clear, especially on certain trash packs or bosses with movement impairing effects (e.g. last boss of Azure Vaults Umbrelskul with the permanent slow Oppressive Miasma).