-PvP- Completely broken for some classes and I mean broken going from both sides of the spectrum, from classes destroying everyone, to classes that can't even kill another player. It's fairly common for a weak class to lose to a powerful class even if the weak class outgears them by 50+ ilvls. That's how broken PvP is and Blizzard doesn't seem to know what to do to fix it other than do blanket damage nerfs/buffs as those are the only changes we've seen.
Alpha Beta PTR Classic 1.1.0 1.2.0 1.3.0 1.4.0 1.5.0 1.6.0 1.6.1 1.7.0 1.8.0 1.8.4 1.9.0 1.10.0 1.11.0 1.12.0 Burning Crusade 2.0.1 2.0.3 2.0.4 2.1.0 2.1.2 2.2.0 2.3.0 2.4.0 2.4.3 Wrath of the Lich King 3.0.2 3.0.3 3.0.8 3.1.0 3.2.0 3.2.2 3.3.0 3.3.3 Cataclysm 4.0.1 4.0.3a 4.0.6 4.1.0 4.2.0 4.2.2 4.3.0 4.3.2 Mists of Pandaria 5.0.4 5.0.5 5.1.0 5.2.0 5.3.0 5.4.0 5.4.7 Warlords of Draenor 6.0.2 6.0.3 6.1.0 6.2.0 Legion 7.0.3 7.1.0 7.1.5 7.2.0 7.2.5 7.3.0 7.3.5 Battle for Azeroth 8.0.1
The Hearthstone has a cooldown of 30 minutes, but there’s a guild perk called Hasty Hearth that shaves the time by half, giving you a strong incentive to join a guild. Yes, even if it’s some random guild that invites you without warning. It may feel odd to join people you don’t know, but if they have Hasty Hearth (and most guilds do), joining can save you a lot of legwork.
Once you have your potions, proceed to complete all the bonus objectives in your starting zone. This should easily level you to 92, where you can proceed to Gorgrond. Interesting enough, for some reason many Gorgrond quests are worth nearly double the experience of quests in other zones. Maybe this is a bug, maybe intended, I'm not sure. But I actually recommend you do all the quests and bonus objectives in Gorgrond. For your outpost choice, I recommend choosing the Gladiators, since they give access to more treasures than the shredder IMO. 

Spoiler: A lot has changed. It can feel daunting to jump into a huge world of which you know very little, and World of Warcraft is gigantic. You will feel overwhelmed if you just rush in. As a returning player who used to write for the freakin’ World of Warcraft magazine (RIP), even I find it hard to figure out exactly where to get started adventuring if I haven’t played the game for a while.
Leveling used to be a treat in WoW. New, unique abilities drove you forward and made getting past the horrible grind worth it to some extent. Now it just feels like everything is set to grind. More than it used to be. Once it was tolerable, rewarding even, but now you grind to unlock an allied race through reputations barely connected to most of these races, only to have to level up that character to get their unique armor set (compelling you to not just boost your character and instead suffer through the slog of ANOTHER group of alts), then you get back to current content and grind some more with a random chance to drop the item you need to get your ilvl up to finally enjoy the single warfront available (as I write this).

Tiragarde Sound and Stormsong Valley are both fairly similar zones, but Stormsong is a little longer, meaning that you might not even have to finish it to hit 120. Tiragarde also comes with a bit of a warning. There are plenty of side quests to do in the zone after you finish the story quests. Don’t do them. It’s not worth the time or the experience you’ll get.