If your children are any thing like mine I'd guess your 2 and 5 yr olds will take it or leave it, your 8 yr old will probably enjoy several things. Our kids are 4 and 7, last year at 3 and 6 - all we visited was the two pavillions which had rides - Mexico and Norway. We may do a little more this year. I would think the younger kids will not stand still for China and Canada movies - ours certainly would not stand that long. IMHO - standing while watching a movie is no fun - I'm just as bad as some of the kids - wanting to sit on the rails rather than lean, and wanting to sit on the floor. Our kids would probably fall asleep during American Adventure - too long, not exciting enough, they may make it through the France film since it is shorter and a little more entertaining.
My 7 yr old likes crafts some days, while the 4 yr old has very little patience for any stand still activity. So the Kidcot stations have only limited appeal. Our kids will probably like some of the entertainment - music, juggling, mimes, etc.., and will probably want to stand in line (if is not too long) to get a few character autographs.
We do not spend more than a few hours in WS, at least for our family there are much better uses of our time.