I can see that there are many attempts made in the past to define the whale on Hive platforms. I am seeing that this definition you have provided here in your post is completely new and simple to understand.
I would be honest, I read both the definitions given here in the comments section, but it was difficult for me to understand where to get these Mvests and why the definition was complicated.
I mean it could have been as simple as some one with 100 hive should be called a minnow or 100 thousand hive should be called whale.
In your post the definition is quite clear. Anyone with exact POB power and the vote value above a threshold is whale. Both these parameters can be seen in the wallets.