Loot filters won't help with distinguishing the different types of greens though unless one is willing to memorize all of the prefixes, etc. It gave me a headache trying to plug in my equipment on Grimtools.
Yeah, life steal is nice when it works. I had my nightblade dual wielding a pair of lvl 45-ish weapons that converted % damage to health until I found something that gave me much higher dps at lvl 55.
When it comes to resistances, I have everything maxed at 80% except for Bleed @ 35%, Aether @ 74%, and Stun @ 15%. I can probably get those that are lacking much higher, but then my damage tanks, so I just have to keep farming. I have some nice elemental retaliation damage going on the character, too. It makes a big difference when you have a lot of trash coming at you.
Finish the story and all of the side quests with the story first, keep the expansion for later. You need to get the reputation maxed out on all non-expansion factions or almost all of them so you can get those sweet sweet +%resistance items you can just stack onto existing gear (and to buy the Reputation bonus items for other characters so you can use this advantage earlier in your future playthroughs). That's where you go to fill in the blanks in resistance for whatever setup you have. Stun resist is best boosted through this as well, on top of what you can get out of your Devotion points. You have to go to Ultimate to get sufficient reputation though, and that's also where you really start needing those maxed resistances. Prior, the focus should be clear speed and damage, survival is secondary because deaths aren't expensive just yet. Unless you play hardcore.
Additionally you can use items to boost whatever type of conversion you have going on, and the lifesteal one(s) are very valuable. Hollowed Fangs, if I remember right.
Have you tried a Nightblade with Amarasta's Blade Burst? Its mental and I see you're already converting to Cold and focusing elemental dmg. You might have better dmg output with it than Sacred Strike plus inherent AoE, also, you
need Lethal Assault, its a buff on all skills, not just Blade Burst, and it adds absolute dmg numbers which is great. My best Nightblade combinations always have been Acid/Poison based, I have several and also one with Amarasta's BB, which is by far the strongest build I've ever used. I can share if you want

NB/Occultist is great for this. NB/Oathbreaker is another really cool option.
Your current path doesn't seem optimal, unfortunately, because Nightblade has just cold synergy and none in fire or lightning, while Sacred Strike deals Elemental damage which is made up of 33% of each element. Also, it converts 100% of its physical damage, so there is no room for additional conversion to a specific element either (and I hope you know: you can only convert ONE time, so you cannot convert any elemental damage resulting from the initial conversion to something else!). Perhaps your idea could work, but then by swapping Sacred Strike with Cadence (which replaces your Arcanist choice) and focusing on WPS attacks on top, since NB and Soldier both have several great ones. Sacred Strike itself is a match made in heaven with Arcanist and Inquisitor, more so than NB.
Another aspect of Grim Dawn later in the game is resistance and defensive ability shredding. Are you stacking -% Resistance, -# Resistance, and Reduce Resistance on your skillset and devotions? -Defensive Ability is another great one to have to increase your crit rate by miles. This is also the main reason to pick a second class: passive or active buffs that shred resistances or increase your OA/DA and/or reduces that of the enemy. This is where the big damage is.
Loot filters won't help with distinguishing the different types of greens
I just pick them all up and sell them off, because honestly, you can use the money if you roll multiple characters, for reasons mentioned above (buying those items).
Here is the bigger Grim Dawn topic on TPU!
If you're wishing for a TQ2, you should check out Grim Dawn, the spiritual successor to TQ being created by the lead designer from Iron Lore. Currently, they have a successful campaign on Kickstarter (http://www.kickstarter.com/projects/crateentertainment/grim-dawn) but there are only 6 days...
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