I used to do "key runs" semi regularly before the nerf limited them to once a week and the Black Lion Chests were redesigned. Recently (a couple of months ago), I decided to give them another try. 

My new key farming strategy is this:
1. Collect as many keys as possible through personal story-aka key runs (there are a couple other methods too).
2. Optimize your wardrobe for the Guaranteed Wardrobe Unlocks (you probably only have to do this once)
3. Open your chests. I've decided to do this on the first day the chest rewards change.

I'm happy to report the first cycle of my plan ended yesterday in success. I had 14 keys collected. The new once a week key farm is way more relaxed and feels like less of a chore. Of course, it's a experiment in extreme delayed gratification, but I did enjoy watching my collection of keys grow over the weeks.

Here's what I got from my orgy of chest opening:

I made my husband do this with me (that n = 2 experiment) and he got two elemental swords. Overall, I concluded that it's definitely possible to get all trash, but you will most likely get at least one uncommon or rare reward (it might even be something you want). I'll be starting the cycle again next week.

I plan on doing some blog posts and a video about my key run strategies and wardrobe optimization as a refresher for interested vets and to help newer players who haven't had the time to think about this stuff yet.

Stay tuned!

SPOILER ALERT: Let me know in game if anyone wants to come visit my jackpot. My home instance is now missing only two nodes