Not that I don't think panel time is 100% unimportant, but Cook and Nami are still and will always be a lot less relevant than The Grandmaster. This means, to me at least, panel time does not hold an utmost importance.
I mean, Kin and Momo's panel time will likely always surpass Shanks and Mihawk's. But, does anyone really think Kin and Momo are more relevant than Shanks and Mihawk? Last popularity poll answered that.