When are you going? If it's before the new TSL opens at HS, no way would I do two days there.
As for Epcot, it just depends. When we took our kids at just shy of 3 and 5, it was eh. The 5 year old loved Soarin and the 3 year old could have gone on Figment all day (help me!) but other than that it was totally eh. This time, at almost 9 and 11, the LOVED it. It was the 9 year old's favorite park, which I did NOT expect....but TT and Soarin were just the right amount of thrill for her. She loved it so much we added an extra park day on our departure day so we could go again.

So...I really think it just depends on your party!