I went last December with a 2yr old (almost 3) & 4 year old (just)
We did 6 days/5 nights.
We spent 1/2 day in the studios and the rest of the time in Magic Kingdom. They loved every minute and would have quite happily stayed longer!
As they're so young if you go for longer you can really take your time. If they wanted to go straight back on a ride we did just that. We never had to be thinking what haven't we seen yet - we must start queing for so and so.
We went on Dumbo 3-4 times a day, buzz Lightyear 3 times a day and I've lost the count of IASMAO.
We also left the park around 4.00pm one day and had a lovely swim in the hotel pool. They loved this as much as Magic kingdom!
Have fun