I think all these recommendations are for a disney NUT. If you absolutely LOVE Disney. If you just love Disney, from what I've seen said, 1 day is more than enough at HK. Likely 2 days at SDL, although 1 may be enough if crowds are light. THey don't have a ton of rides there.
As for Tokyo. I absolutely LOVED Tokyo. I went one day to both parks, and rode everything. The TDS day was normal SUmmer crowd. The TDL day was a CRAZY CRAZY HAPPY FUNTACULAR JAPAN crowd day. I waited 45 minutes for a Pooh FP at opening. I guess I didn't get on BUzz, and MOnsters Inc was being built. Plus I skipped lame rides such as Jungle Cruise and such. I rode all the mountains, Pooh twice, Pirates (which was a waste of an hour), saw the Mickey Mouse Review which almost made me cry as I recalled seeing it as a little boy in Orlando, and didn't realize it still existed.
But, neither Tokyo park has that many UNIQUE rides if you've been to DL and WDW. TDL's BTMRR is a unique layout, and Pooh and Monster's are unique. I think Buzz, PP, HM, and Splash, and Philharmagic are all WDW clones. Pirates, SM, and RR are DL clones. ANd for the most part, the TDL rides aren't really "plussed" versions either. But everything works, including hopping Brer Rabbit.
DisneySea has a few unique rides: 20,000 Leageus and Journey are at the top. But both rides are VERY short, especially Journey. THen they have a very long Arabian Nights dark ride, and the whole Little Mermaid area, which is only kiddie stuff, and a small unique coaster that you have to hit early. TSMM and Tower are clones. Yes, Tower has an awesome preshow, but the ride is a clone. Both Indiana Jones rides are clones of DL and Paris. The main dark ride is plussed from DL for sure, but not so much you'll be begging to ride again if you hit DL regularly. Then there are some unique smaller rides and shows.
So, as you can see, TDL is absolutely an amazing resort, but I just can't recommend people spending 4 days there while they are visiting Tokyo and the gazillion other awesome things in that city. And it is waaaay out to the West side, and the train transfer to Disney's train includes like a 3/4 mile walk.