Set sail for the previously unmapped isles of Azeroth. Battle in groups of three as you race against cunning rival intruders—or enemy players—to collect the island’s resources. Constantly evolving challenges await as you traverse frozen landscapes near Northrend, open the gates of an abandoned Gilnean castle, navigate a war between elementals and more. Tides of Vengeance adds two new Island Expeditions to the mix and two new random events, as well as updated rewards.
At 98 you have the option to drop what you're doing and return to your capitol city to start the quest for your Legion Artifact weapon. However, I do not believe this is necessary to do right away unless you're struggling with kill speed in your current gear. I would recommend waiting for a natural pause, such as hearthing to repair and clear your bags. From 100 to 107 you won't even really fight mobs that often; only just enough to clear the way to any treasure you need to pick up.
Update: The reason for less experience from gathering is due to how Blizzard revamped professions and broke them down by expansion. In order to get full exp from gathering you'll simply need to find a profession trainer for the relevant expansion. (WoD you just mine or herb the first one ypu come across and the game gives you a scroll for learning WoD gathering).
Obtaining Items from the Black Market Auction House Everything about the Black Market Auction House, including unique items for sale, how to place bids, and where to find the Auction House. Professions in Battle for Azeroth Professions in Battle for Azeroth, the next WoW expansion after Legion, have received a significant update, with many new recipes as well as a significant skill squish. In this overview, we'll highlight the major recipes, reagents, and useful items each profession offers. Obtaining Blizzard Shop and BlizzCon Vanity Items How to purchase and collect all of the mounts and pets from the in-game Blizzard Shop and special promotional events like BlizzCon. Obtaining All the WoW Trading Card Game Items Learn all about the quirky Trading Card Game items, from spectral mounts to weather machines, as well as look-alike items that are easier to obtain.