No. There is a nifty equation that transforms the defence number into % damage mitigation.
→ Having X defence means incoming damage will get reduced by Y%.
And due to how the equation is set up, damage mitigation never exceeds 85%. So even if you had a billion defence, you'd still take damage.
It also depends on the content you're playing, for instance Clan boss teams ( save for unkillable teams ) can benefit more from stacking defense as opposed to HP, on teh other hand if you're going up against enemies that ignore defense ( for example Dwarves Faction wars 21 boss ) HP becomes more valuable.