Being complicated has never been the issue for KH. Lots of games have complicated plots, lots of JRPGs have complicated plots, the thing is, people actually care about that plots and what happens in them. They care about the characters, they care about the events and how it effects them.

Outside of Sora and his main friends, do you actually give a shit about KH's plot? Do you actually care about MoM's evil vague plan or do you just think you do because they're cramming it down our throats? Do you actually care about the Union X and Dark Road characters or do you want to see how they relate back Sora? Even the Disney worlds there's nothing to really be attached to, because they aren't allowed to be anything more stand ins for their actual characters or be in any actual danger when they aren't following the plot of the actual movies to a T.