As far as boring, let me put it to you this way-- when DD was 2, we allocated one full day of Epcot open to close. It was not enough for her. She absolutely loved Epcot. After 2 hours at AK, on another day, she begged us to leave AK to go back to either Epcot or MK. We have been back to WDW twice when she was 3, and once when she was 4, and each time we have spent 2 days pretty much open to close at Epcot. AK is a half day park for her. Not enough Princesses. We have a really good zoo at home, and as much as I personally like AK, she wants to ride Safari, see the Lion King Show, meet some characters and get out. She has no intention of spending her Disney time looking at animals when she can do that at the zoo at home. She wants Princesses. Plus, where Epcot and MK have a lot of rides for that age group, AK really doesn't. There is Safari, and there is Triceratops spin (which is really just a lesser version of Dumbo or Aladdin's Magic Carpets in DD's opinion).
DD can spend an entire afternoon in World Showcase at Epcot just going from Princess to Princess and stopping to watch the entertainment. She would ride the boat ride in Mexico around in circles all day if we let her. That is one of her favorite rides on all of WDW.
She also really likes Soarin because it is "flying". Nemo and Living with the Land are big hits as well. She isn't crazy about Test Track- too jerky and she hates the "hot room". She will ride it, but she has to be bribed onto it.
As far as spending just 2 hours there, you are right that you don't understand the size. Walking from one end of World Showcase to the other end (half the park), is about a mile.
To give you an idea, we get to Epcot usually right at 9:00 a.m. opening, or at the lastest by about 9:10. I run with the tickets to get Soarin FPs, while DD and DH go get in line to meet Mickey and the Gang at the Character connection- (usually stopping to see Daisy and Stitch who are out in the mornings at the front of the park). After that, we ride Nemo and wander the Aquarium after it, then DD usually wants to see Turtle Talk with Crush. We then go and ride Living with the Land (a 20 minute ride). By then, it is usually time to use our Soarin Fast Passes. By the time we have finished Soarin, we are usually booking it at a fast pace to try to make it to our 12:30 or 12:45 ADR at Biergarten (One of DD's absolute favorite restaurants at WDW due to the German band and dance floor). So, after 3 hours at Epcot, we have barely scratched the surface.
If you really only have a limited time, for a 4 year old girl, I would say you definitely want to do the boat in Mexico, Living with the Land, and Nemo. If you could get FPs, I would say Soarin, but it is probably doubtful that you can get FPs, in the time period. Test Track mid-afternoon, it is doubtful that you can get FPs that will kick in, within the 2 hours you want to spend at the park, and the line could eat up most of your Epcot time. If you asked my DD and told her she could only have a few hours, she would think the most important things in an afternoon at Epcot would be to ride the boat in Mexico and walk around World Showcase meeting the Princesses and other characters.