I would rather run Tanaan multiple times on different characters a day than do one more day of Suramar, World Quests and Withered Training. You either got something or nothing (yay, 300 oil!) in a much more condensed time frame in Tanaan versus Suramar/WQ/WT.
Withered Training you're supposed to fail by design over and over and over again until rng provides you with all of the upgrades for your Withered units. Not fun. I've been doing this fairly consistently, gotten nothing but vendor trash and minor rep gains. The reward for doing World Quests falls off pretty quickly. I wish Emissary Cache rewards scaled with your character so that they actually held something useful or worthwhile. I would mind the repetitive design of the world quests less if they led to something worthwhile but they don't. I don't like Suramar, at first it's impressive that it basically has the scale and population of an actual city and then you quickly realise how much of a pain in the ass it is to navigate. You need all of those warp points and flight masters whistle just to make it tolerable to get around.
Also I don't get why the Burning Legion needs to rely on a bunch of magical crackheads who basically can't leave their own city for more than a day or two with what we saw on the Broken Shore scenario. The Legion were basically teleporting in a massive and unstoppable army and need to rely on the Nightfallen because of reasons?