The Horde will now control most of Kalimdor, and the Alliance most of the Eastern Kingdoms. For a low-level character the quests and storylines won't change, but for high-level players many zones will see changes via phasing. Teldrassil is burned and Undercity is in ruins as the story progresses by phasing. At max level Arathi Highlands and Darkshore are phased to be updated to reflect their status as locations for Warfronts.
That’s because armor of higher level has higher Azerite power requirements than lower level armor. That means a shiny new piece of Epic gear will have better stats but, unless you’ve been diligent about your Azerite power grind, won’t have as many traits unlocked. You lose options as you earn better gear. Eventually, you’ll grind out enough Azerite to earn those traits back, but you’re left with limited customization until then.
As others have said, there are free alternatives... which is important to consider if the price of the Zygor Guides are a concern. If speed and convenience are more important, then they're worth it. Zygor will take you through the quests in the most efficient way possible, and their customer support and the speed with which they update the guides when changes are made to the game is impressive. I know I went from 80-85 a heck of a lot faster (in /played time) than my co-worker who doesn't have the guides. And we had a bet going to see who would make it first. For me, it was worth it. Your mileage may vary...
Eventually, the Alliance finishes its preparations and launches an attack on the Zandalari capital of Dazar'alor, their goal being to sever the budding alliance between the Zandalari and the Horde by dismantling the Golden Fleet and capturing King Rastakhan. Despite Anduin and Jaina's desire to capture him alive, Rastakhan is overwhelmed by the power of his pact with the Loa Bwonsamdi, and the Alliance champions are forced to slay him. Enraged by Rastakhan's death, Horde champions launch a vicious counterattack on the withdrawing Alliance forces, which ends with both Jaina and High Tinkerer Mekkatorque gravely wounded. As the Alliance leadership debates their next move, Sylvanas, infuriated by the Horde's defeat, resurrects Jaina's long dead brother Derek Proudmoore as a Forsaken, an act that horrifies the surviving Horde leaders, with the intent to use him as a sleeper agent to destroy the Proudmoore family from within.
Lightforged draenei (7.3.5) - "For untold millennia, the Army of the Light waged war against the Burning Legion throughout the Twisting Nether. The draenei most committed to their long crusade would undergo a ritual to become Lightforged, infusing their bodies with the very essence of the Holy Light. After finally achieving victory on Argus, the Lightforged Draenei have undertaken a new mission: protecting Azeroth from rising threats and helping the Alliance push back against Horde aggression."
TSM has a very steep learning curve, as it is a total profession framework. It does not hold your hand, and requires a lot of setup. Luckily you can import settings from other players and there are a ton of settings out there. I have published most of my settings in my pastebin here. You can also check out Sheyrahs. TSM recently upgraded to version 4 and I have a written guide for TSM here that is currently up to 11 parts covering all of the basic functionality.
Engineering is a crafting profession that primarily revolves around fun recipes. The gold-making potential from engineering is limited in terms of Legion recipes. The Skullblasters can be obliterated for profit. Engineering has a lot of profitable old world recipes, primarily mounts and various unique effect items and toys. This profession is best relegated to an alt unless you love the lore-aspect or have other sentimental reasons to keep it on your main.
I have tried it a few times. It's good if you're new to the game. Otherwise not so much. I found I leveled slower by using it, as it's suggesting to take the longest possible route usually. Basically following roads everytime, when you could take an easy shortcut. Especially if the shortcut involves a bit of fall damage, it's out of question. The "go here" spots don't also update if you take a shortcut, and then the waypoint arrow points to wrong direction. But perhaps it has been updated since then.
-Island Expeditions- Island expeditions was one of the new features I was looking forward to but Blizzard no longer makes games that are ready when they are ready but rather makes games ready when the deadline comes. Thus, many of the new features are completely stripped down from what was expected and it's literally just a small scenario you enter with two other players to continue to grind out your Azerite neck piece.
Good question. Me personally, when I use a new strat from somebody else, I always read thru the strat, and in the case I really need to level some pet, I then (likely) exclude strats that are mentioning things like “RNG”, “risk”, etc. But: I’m always happy (when using a new strat) when I see some detailed infos, so that I can estimate what is going to happen. But YMMV.