Not going to happen. The leashing mechanism was one of the things that made it so easy for junglers to gank with near full HP because most junglers could clear blue and take little damage. This also allowed for a faster clear of the lizard buff and even stronger ganks.
Riot have made it clear with this patch that ganking needs to be a trade-off. If you want to gank with red, you'll have to do it with lower HP (and therefore greater risk). However, if you want to stay in the jungle, you will be rewarded with more XP.
I think it's a fair change and don't see why it needs to be reverted.