My young children have never enjoyed World Showcase. It typically ends up being frustrating for us as well because everyone looks so relaxed grabbing drinks, etc. and we can't even do that because our hands are full pushing strollers and chasing toddlers. In years past, we have done the Akershus breakfast and then just walked around the worlds without stopping much. My kids like the little train near Germany, and that does usually give me a chance to grab some caramels and shop the Christmas store. We did the boat ride in Mexico once, and that was fine, but not a huge hit for anyone in our family. Other than that, we just walk through, stopping for characters if the kids see one they're interested in. Epcot has always been a half-day park for us. My kids are now 8, 6, and 2.
That being said, we are planning a trip for next February, and I'm planning to *try* to spend a little more time in World Showcase now that they're getting a bit older. We are planning to do Frozen Ever After, lunch at Via Napoli, trains / caramels in Germany, pick a pearl in Japan, dessert in France, and the maze in UK. I think we will probably spend 2-3 hours there, which is more than we've ever been able to do.