Going from the AA area to the Lounge Pacific is a really, really long trip for a very mediocre lounge. I'd consider it a big waste of effort.

Here's the deal with air travel in Japan: the lounge is not an important part of the experience. Neither JL or NH put a lot of effort into their lounges -- it is just not something that matters to the Japanese premium traveler. The ones they have are fine, but nothing special. It is certainly not worth going out of your way to find one.