Restricting sources of % inc life allows the devs to keep a tighter control on life values . Control of this is a major lever to control the power creep of the game . If the creep shifts , then we get something like our current situation . This time last year , people were wondering why , if ever , people would want to waste their time playing CI . First a rough comparison with ES . ES is inherently weaker than life . You have to make , and sacrifice , certain build freedoms in order to use ES as life replacement . Furthermore , even with all the applicable ES keystones and gear , you will still never replicate the full versatility of life . Status ailments , stun , pot choices , regen v . leech , spreading passives all over the tree . Taking your build ES introduces a whole host of problems that you have to overcome that life can take for granted . GGG has had to , and likely will need to , alter the avg . % inc life and base hplevel . In order to do so , they had to make sweeping changes to the skill tree . Imagine the headache of hundreds of thousands of legacy rare items . The nightmare is still affecting some of our favorite uniques that are , in effect , unplayable as they were not altered . Ming ' s Heart , Carnage Heart , etc . If that were to swing the other way . Well GGG would be unable to make such a change . And without being able to use that design space , they would not be able to balance the game for future power creep .