Board Thread:Improvements and Issues/@comment-29325824-20200518112359/@comment-5398287-20200519012233

Vast seemed to be used exclusively for Ichigo and Kenpachi to indicate that they had both immense power and little to no control over it - that was phased out when Sal added the Reiatsu Control subsections, so it became Immense Spiritual Power -> Novice/Unruly Reiatsu Control.

As for your suggestions, Timjer, I like them on paper but also wouldn't want to see them used in this specific context for different reasons: Overwhelming is used specifically for Ulquiorra's Segunda Etapa power because of the unique sensation his Reiatsu produces there, Transcendent implies something like Hōgyoku Aizen and thus shouldn't be applied to every character in this tier of power, and Incomparable...well, if multiple characters are described with that level of power, the term contradicts itself. After using the mighty power of thesaurus.com, I'm thinking either Colossal or Monstrous (a surprising amount of synonyms for "immense" relate to infinity or endlessness, which kinda limits options - also, "barn door" is considered a synonym, for some reason.

Imagine, if you will, Barn Door Spiritual Power.)