First of all, this is a old topic that pretty sure everyone has overcome. I have farmed darkmoor four or more times everyday since couple weeks from now. I find it crazy because from all those times I have never gotten a single piece that's tier 3. (Best one) When I used to farm darkmoor back when it came I was never a hitter because I was a jade and darn it took forever to get my gears on ny wiz and now that I am a hitter nothing, I always thought that hitter usually get rewards. You might say that you prolly died half through the battle but I tell you NO, cause I got my ice helping me through all runs. I have tried chest before and I spent over $60 on my balance wiz and damn I got nothing. I would try it on my storm but I don't want to have bad experience on it or waste more money than I already have. It's a bit frustrating cause I waste my time on something I gained nothing from. I've have worst experience on my balance and hail eu I'm finally done with him. I mean why can't just the hat drop for me! I hope no one takes this srsly i just had to tell my bad experience and luck and let go of my frustration.
My suggestion is to slow down, take a breath ... and only do one run per day.
At the end of that one run, only use the chest 3-4 times, total - otherwise you are seriously wasting Crowns.
My personal rule of thumb is to stop using the chest when the cost hits 200 Crowns. That's already a LOT of crowns (50 + 100 + 150 + 200 = 500). No matter what, at that point I stop and repeat the dungeon on another day if I still don't have the gear I'm farming for. Every use just adds the price higher and higher ... and the clock doesn't reset until I've stayed away for over 24 hours.
Another thing you can try is the exalted, single-shot dungeons. They seem to drop great gear very quickly, and a lot of the items are comparable to Darkmoor, if not actually better in some cases. I see a lot of people wearing Rattlebones and Krokopatra gear.