It's a pipe-dream and not meant to be taken seriously. But its an interesting idea anyways.
An item, ability (new champ), or some form of interaction that'd break down mountains/walls through the jungle. It could also be an item that spawns one of those "ALLY ONLY" portals that are on the walls of each teams base.
It would have to have a very long cd, and have a very long interruptable cast time, and probably provide some form of xp for spending your time casting it.
Probably be a jungle/support item. It would open new paths to buffs, (dragon/baron pit "Backdoor", or a path from spawn straight to blue buff, cutting out a straight line from wolves to blue.) Top laners could use it to open a new gank path for their jungler to access the lane.
Bushes could over-grow the area that is broken up so that its leads to new interesting areas to place wards.
Again this isn't a serious consideration. But an interesting idea none-the-less.