minecon 2012 mod api we want to remove features.

The datapacks are nice. But why cant we remove features like mojang promised over 12 years ago? 

It should be simple to add game rule to change attack cooldown to pre 1.9?
It should be simple to add game rule to disable sprinting.
It should be simple to add game rule to disable hunger/revert hunger to beta 1.7.3

So many lost promises.