Buying individual legs for a two week trip usually came out to be the same for most people anyways. The JR Pass rarely made sense (especially with the restrictions on riding the fastest bullet trains) and now the price reflects that.
Now it will cost more to go to Hiroshima+ and so less people will do that.
I don't really see the logic behind that myself. Tourists will still travel between those two cities. They will just travel less to other places that they don't prioritise as much.