Arms is the best leveling spec for Warrior in Battle For Azeroth. Fury is a great single target spec, but lacks the AoE needed to compete with Arms. You will be striving to fight 2-3 enemies at a time for optimal results and Arms has the perfect spells and talents for the job. My tests have shown the average amount of mobs you will fight at once is around 2.3, which makes Sweeping Strikes amazing for leveling. Perhaps my favorite combination in the game is Avatar + Ravager + Sweeping Strikes. It slices down large packs of mobs in seconds.
":" - Any time a step ends in a ":" instead of a "." means that the next step is part of the current step you are on. This generally means the next step should be done while working on the current step. This means every "start working on" or "continue working on" will end in a ":". But this is used with other occasions as well, so keep this in mind.
While the expansion kicks off with heavy references and scenes of this war, leveling through the Horde side of the new content it barely came up again. Except for all the times I had to mine Azerite to make sure my faction was the leader in the Azeroth version of a nuclear arms race. The Alliance side of things had some heavier references to to the war, at least in the portions I played, with one scenario in Stormsong Valley where a fleet of Horde aggressors bombed a town.
So, the initial leveling process is probably the longest it has been in an expansion in a long time. My first play through, it took me about 12 hours to finish every single quest in every single zone. Needless to say, due to leveling 7 times, my last leveling was done by a ret pally and took me just over 8 hours and completed every quest in the Horde zones. There are a few tips I would like to give for leveling in BFA.
I'm very, very interested in a guide that takes into the following: 1) Dungeon finder; and 2) Heirloom items. I've never helped with a guide before, but would be open to help in collaborating on the project. With the leveling guides I've used (primarily this one) I, too, find that I level at a rate that throws the pace of the guide way off (not its fault at all, I can't say enough good stuff about the guide) to the point that I get frustrated and just queue up for dungeons.
Professions: This may seem strange for a leveling guide, but the first opportunity you get, pick up both the Mining and Herbalism gathering professions. Not only will this allow you to track many various quest objectives on your map, but you also get a fair amount of experience whenever you gather. I'd put it at around 10% of a quest turn-in per gather. Since most of your wasted time in WoW is travel time, stopping to gather ore or herbs can keep your exp/h rolling as long as you don't go too far out of your way. You should only gather if it's convenient, and on the way to an actual quest objective. Don't make gathering your priority.
For your tank... I'm assuming you meant which race should you be, not which class, since you seem to want to be a warrior! Well, if you were Horde side I'd recommend Tauren for the health buff. But honestly, I *never* pick a race based on the racial features - only based on the flavor. If you are going Alliance side, I am quite partial to dwarf warriors myself but pick whatever seems most fun to you!
At Level 78, you unlock the stat Mastery, which increases your Shadow damage. When you unlock this stat you should switch your level 56 talent from All Will Serve to Clawing Shadows, as it benefits more from the Mastery. The mechanical change when using Clawing Shadows is that you will be able to pop Festering Wounds from a distance. If you want to attack multiple targets with Clawing Shadows using Death and Decay's cleave effect, make sure you play the Death and Decay below your own feet instead of the target.
Something to keep in mind as well is that this will make enchanting materials more valuable, since it is likely most players will now simply scrap their boe greens instead of getting them disenchanted. Also redundant dungeon/raid gear can be scrapped rather than traded to the (guild) enchanter in the run. Less stuff gets disenchanted, meaning there will be less ecnhanting materials, meaning their value will rise. All the more reason to DE rather than scrap as an ecnhanter.