One thing I've thought about for group jumping, is that a character's Strength affects how far the can jump. This is probably why it hasn't been implemented yet.
Certain characters in your party won't be able to jump to certain places; or if you use the max range of your strongest character to make a jump that usually all your characters could make, how is the game supposed to know that all your characters can make it?
It's probably harder to implement just because of this. I don't think this will prevent them from adding it at some point, and I'm sure they are working on it, but it's something to think about.
