My wife and I are each Diamond independently and we stay at this hotel fairly regularly and ALWAYS do the 6,000 point suite upgrade usually grabbing two suites at the same time. In Japan, its silly not to upgrade - so good job planning it this way - usually the corporate rates or the "special" rates on sale are not very much lower than the prevailing, and in Japan, the suites are SO MUCH BETTER than the regular rooms, that to NOT do the suite UG is almost criminal in my book.
You'll get a Park Suite and they are all reasonably similar absent the direction they face. I would say out of 10-15 times we have gotten a Fuji facing one 40% of the time. Frankly I prefer the non-Fuji facing ones. Fuji is pretty far off and you can only see it about 20% of the time (dependent quite a bit on what month you are going, but even then still fairly variable). I would rather have a guaranteed view into the huge skyscaper district than a possible view of a heck-of-far-away mountain if visible usually only through haze...so YMMV but I actually would think you're lucky if you do NOT get it!
What's funny is knowing the great service in Japan I would not put it past the PH that next time I check in I have a great skyscraper view, and they say "oh, we happened to see your post on FlyerTalk"...
Great hotel, enjoy it. We're about to head across the pond for 8 days and are doing 4 at the PH and 4 at the GH. They are both so terrific in their own ways. I can't get over how awesome the new teppenyaki place at the GH is! Hyatt in Japan is outrageously good - go Hyatt! ^