I agree that the lvl90 itens rates of sucess should be changed and i also agree with the energy crystal. Also in my opinion beginner itens should have an increased rate of sucess, to help the new players progress faster to midgame stage.
On the high level itens, in my opinion it should stay this way.
It is suppose to be hard and a longway journey to conquer the full+9 endgame stuff. Othewise in a week everyone gonna be full gear and quit the game cuz no objectives