OK problem number one is that power numbers are difficult to understand. No matter if they are in kv or watts. Second the numbers are differrent from manufacturers, perhaps by the way they are measured or calculated, which further skews the meaning of the power rating.
So how do we as a whole hobby/community/industry come to a standard way of measuring power for both brushed and BL motors? There should also be a standard for the construction of a motor dyno. This is probably a question that is more toward engineers than hobbyist, but still we need to find a solution so that the numbers you get for a power rating are the same across the board.