If you are just coming out of Level 110, you will probably have a number of different Legendary items to choose from. Your Legendaries' special effects will stop working at Level 116, but until then they can be a very powerful addition to help you level quickly. These are our Legendary recommendations for leveling as an Unholy Death Knight in Battle for Azeroth.
Grinding mobs is tedious and slow. Questing is much faster since you get the massive quest experience in addition to the monster's experience. There is no grinding in this guide - you can go through every single level by simply questing! There is minimal traveling time as the guide leads you visually through maps so you can quickly rack up quest experience.
This is also the reason why when I read in WoW forums of people skipping guide sections, due to being too low level I'm not agree and start ranting about it: it'll be a mess syncronizing with the guide and I've seen many people complaining about missing quests or accusing the guide for being innacurate, but not realizing that was their fault since they're skipping and missing a lot of quest chain requirement. Of course this apply if you're following a guide, believe me, it's very frustrating when you remain stuck in a guide section due to the reasons I've mentioned, more than doing grey quests (but they allow to be perfectly in sync with the guide) and goiing here and there to get the pre-requisite quests.
First off, there is no reason to ignore the war Campaign, you need to do them to unlock world quest. Beside that, the way scaling works, war campaigns are easyer to do while leveling then at 120. Everything becomes alittel harder at 120, untill you get some gear, because of them scaling levels. Also, i did my leveling on a demon hunter in about 8-9 hours. I think i know what youtube video you talked about, and i strongly dissagree with him. One thing tho, total xp needed was buffed with 15% that in worse case would make me take 10hours, the way i did it.
Edit 20 It’s been a week since this post and a lot of people are still reaching out to me with questions which is fine. I have had a few different people reach out to me to help make YouTube videos based off this guide and more info in BFA which I’m more than willing to do. Whoever gets the videos up first I will link them here for you guys to enjoy.