So I bit the bullet and converted my vet 1 melee DW medium armor nightblade into a destro/resto warlock type to see what all the fuss is about. My NB was always squishy but at least with my melee build I could burst down two mobs in a group of three before I started to take damage. But after going caster taking on 3 mobs is extremely difficult, even in the starting vet zone (Glenumbra for me). I just can't take as many hits and I can't outheal any of the damage I'm taking and my CC sucks. I'm starting to feel that the NB destro/resto is really an endgame trials/group build where there is a tank to soak most of the direct damage and a healer to bail you out to supplement your passive heals?

My melee nightblade bar was:

Ambush (opener)
Concealed Weapon (main magicka dump until <20% health)
Impale (finisher)
Rapid Strikes (main stam dump)
Flying Blade (ranged snare)

ULT: Devouring Swarm (vamp)

I switched to destro/resto with 5 pcs light 2 medium with inferno staff and my bars look like this:

Bar 1 - destro
Crippling Grasp
Funnel Health
Impale
Destructive Clench/Crushing Shock
Siphoning Attacks

Ult: Devouring Swarm

Bar 2 - resto
Crippling Grasp
Funnel Health
Impale
Restoration
Siphoning Attacks

Ult: Devouring Swarm

On either of these I take so much damage especially against mobs of 3 or more. I can't heal through it with Funnel Health and Restoration. Would remorphing Siphoning Attacks into Leeching Strikes help?

And I feel like I need to have some kind of defensive on my bar but the only one that seems to be available is Blur. Is Blur worth taking?

This could very well be a L2P issue but I felt much less squishy as melee medium and could handle mobs better. Any suggestions?