I think the intention is not to remove Rest as an ability itself, but to have some mechanism whereby, in the absence of hostile mobs, or using a power on another character your character would, after a delay similar to that of Rest, get an increased HP and End recovery rate. I would expect that this would be smaller than what you get from Rest, and have limits on its activation that might be too hard to code (i.e., not if any member of your team is in combat, not if hostile mobs are within a range dependent on your stealth and their perception, not if you use a power on another character or pet, etc.).
Correct, the intent is to reduce downtime when truly out of combat in some way instead of having to use rest and stopping your momentum fully.