Hello,
sorry i missed this thread.
We did not forget about those HP values at all.
The Dalanis Nightmare set brings a huge setbonus for each class and also it brings pretty big amounts of matk/patk and crit.
Also look on the other set items and on the setbonus for the stamina bonus.
If you check the history of RoM items, you will see no item is perfect, there will always be another item which will grant you a higher bonus of one value and a lower bonus of another one.
You can choose to use other items with higher HP and lower patk, or use those and benefit of the huge attack bonus.