It didn't take me long to make the switch out of Nightblade melee, there exists a very glaring problem within their class skills. The problem is quite simple, many of their spells' damage scales off magicka, but they are physical moves that also do damaged based on enemy armor and weapon crit.
Because of this, you're really at a toss up as to which armor you should use. Medium armor is nice for stamina because of the bonus to regen, while light armor favors magicka via reduced spell cost and increased mana regen.
Then there exists the problem that if you were going physical dps your weapon skills scale off a completely different resource than your class skills. While soft caps do exist and aren't hard to reach, you still increase your damage by gaining magicka or stamina, but spreading it over two resources means lower damage for each tree, stam/magic.
This will be a serious issue later on when we see better gear with higher vr levels and HOPEFULLY harder to reach soft caps.