I'd like to add my personal experience as of a week ago in regards to illusions: I bought all of them for 10 silver being the highest bidder. They sell for 2-4k each usually, but it's a very slow market with little interest. They might be a nice addition to your portfolio if you can get the mats with little effort, otherwise it's not enough to warrant investing in it. At least on my server.
I don't think that made professions all that useful. And it was a huge burden to the fun of getting new gear. I like that if I get a new piece of gear in a raid I can generally equip it right away. Couldn't do that when half the gear you get need enchants/gems/whatever. Why not just bring back re-forging then? Though I did like upgrading gear when that was a thing.
Island expeditions - 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. Can be done either in PvP or PvE against advanced AIs.
Mythic+ rewards will also go up by 30 item levels; however, during the first week of Season 2, rewards from end-of-run chests will be capped at Mythic 6 quality (item level 385), and the chest you open next week will contain Season 1 rewards if you do a Mythic+ run this week. (So, for example, if you do a Mythic 10 during the final week of Season 1, you’ll get a Season 1 item level 380 piece and 60 Residuum from your first Season 2 chest.)