[Update]: My review for The War Within is now complete, so if you're curious about what exactly the Delves have to offer, as well as how the rest of the expansion fares when compared to Dragonflight, I welcome you to give it a look.
Following in the footsteps of World of Warcraft: Dragonflight, the freshly released The War Within expansion is Blizzard's latest effort at trying to cater to a more casual, solo focused crowd. There's still Mythic+ dungeons and raids as usual, but now you can also look forward to lower difficulty dungeons you can tackle alongside an NPC party, as well as challenging mini-dungeons called Delves that seem to be tailor-made for the crowd that wants to experience WoW's endgame content, just without the time commitment.
What some of this looks like in action, as well as what the actual story is about, that you can check out through the launch trailer below. Have a gander:
I'll have a full review up in a day or two as I'm still musing over some stuff, but long story short, The War Within is a solid expansion that does a great job of embracing Dragonflight's best ideas, though it doesn't do much to really push the envelope forward. So if you're a fan of World of Warcraft and you want more of it, The War Within will serve you well. If you're looking for something drastically different, then I'm afraid you're out of luck.
If you're planning to dive in, I would advise waiting a week or two as right now Blizzard seems to be struggling with server performance. The gameplay itself isn't particularly laggy, but the Auction House is nearly unusable and there are quite a few bugs with how you interact with the NPCs. It's nothing that would completely ruin your experience, but it's definitely not something I'd recommend you put yourself through unless you're really excited to start playing.
Whatever the case may be, I'll make sure to let you know once Blizzard finally cures whatever ails the poor servers.