If you look closely, you'll notice that you've already stated your request and reasons. Now, if you look closely at how boards work, you'll also notice that only admins can change the avatar dimensions. If the admins choose not to change the avatar dimensions, there isn't much you can say to make them change their mind. If, on the other hand, they
are going to change the avatar dimensions, then they're going to do it regardless of the number of times/passion with which you request it (although bugging them about it may make you a nuisance, and not help your cause any).
This board is about
anime music videos, not about your supposed "art in the form of an avatar".
When you read a Manga, are you just reading the words?
Interesting point, except for one thing. This is not manga, nor are avatars. It's so dissimilar as to be uncomparable. The analogy doesn't work.