Vitality has gotten several benefits recently, and this buff is more than welcome.
Not only does one now get more overall hp for investing in vitality, but everyone else now has less hp naturally, making you comparitively gain more more hp.
If you put in 1 point every level, you would get 11 points a level. This would keep your hp the same as if you put in 1 point every level before, but now everyone else has less hp.
This is a significant change for the vitality builds, and for those who planned to lean even further into their tanky nature, we now get 50% more defense from out items.
While some will surely still debate about if vitality will be worth if, this is positive news for us vitality builds.
Go paladins 
Edit: Adding some calculations for previous difference and current difference.
Calculations
All these differences are between Player 1 who puts 0 points in vitality, and Player 2 ,50% of their points in vitality. All of this is made before armor.
Please be willing to point ouf if there are any big errors in my calculations.
(I think hp starts at 100, and i wasnt sure if you get your 2 points for level 1)
With a max level of 120
Player 1 has 1052 hp
Player 2 has 1409
This leaves a difference of 357
With the new change at a max level of 120,
Player 1 has 933 hp
Player 2 still has 1409
The new difference is 476
100 hp, big whoop. Sure this may seem insignificant, but this gap only grows.
Lets look at level 500
So before,
Player 1 has 4092 hp
Player 2 has 5589 hp
This leaves a difference of 1497 hp
This seems significant enough, but now
Player 1 has 3593 hp
Player 2 still keeps 5589 hp
A new difference of 1996 hp.
Significance imo
Even at a high level this will be significant, and will only raise in significance with other percentage hp buffs (such as vitality awakening or defense mode)
Go paladins