i need help with my itinerary

september 21, 2014 - day 1: arrive in tokyo, is half day enough to explore tokyo
day 2: does disney sea take up the whole day?
day 3: we want to see mt fuji. where can we see a good view of mt fuji? we plan to go back to tokyo after seeing mt fuji and go to kyoto the next day. or is mt fuji along the way to kyoto?
day 4: tokyo to kyoto by train
day 5: go home via kansai airport

feel free to give suggestions and revise my itinerary =)

A half day is definitely waaaaay too short to enjoy all that Tokyo has to offer.
If you want a good view of Mt. Fuji, visit the city of Hakone or Kawaguchiko.
You have a painfully short itinerary, so you'll only get a very small sample of the cities you're visiting.

Not two weeks is enough to see everything Tokyo has to offer, half a day is obviously way too short.
Here's what I'd do:

- Completely skip Disney Sea (yes, it takes a whole day).

Day 1: Explore Tokyo (You may tell us what you like to see & do so we can give you some advice about which districts to visit)

Day 2: Explore more Tokyo.

Day 3: Most of people go to Hakone and stay at a Ryokan (traditional Japanese style lodging) on the way to Kyoto for views of Mt. Fuji. You can also stay at Hakone until it's dark and get a train to Kyoto. With such a tight schedule doing this might be better for you.

Day 4: Kyoto (make a list of the 2-3 temples you'd like to see the most). If I had to suggest a complete day I'd do Kinkakuji, Kiyomizudera and Fushimi Inari. Finish your day at Gion District.

Day 5: I don't know which time you have your flights booked but you may be able to do some last minute shopping in Osaka.

However, if you're yet to book your flights, I'd just get to Tokyo.

Tuesday, September 23 of 2014 will be Autumnal Equinox Day, which is one of Japanese national holidays. There may be labors in Japan who will take the previous day September 22 off in order to practically expand the weekend from Saturday, 20 September to be 4 days until the holiday, September 23.

You can make a daytrip, for a view of Mt. Fuji, to Hakone Town in Kanagawa or Kawaguchiko area in Yamanashi from an urban area of Tokyo. To Hakone, you can make a side trip from Odawara City in Kanagawa on your way to Kyoto.

Considering possible crowdedness during the 4 days, I suppose it may be better to make a daytrip to Hakone or Kawaguchiko on September 22, which will be a weekday between a Sunday and a holiday, and tour Kyoto City mainly on September 24 and 25, which will be normal weekdays.

P. S.:
Please make sure that you pay attention to official information on typhoons when one may approach Japan around the time of this journey.
http://www.jma.go.jp/en/typh/