IHMO the best thing would be a key changer.You get an dragonflight key after a dungeon like in SL, but there is an NPC in the hub where you can change it to "old content key".People who like/want the new dungeons, can run them. People who like the old one, can change it.Would be way more work, but shouldnt be a problem for a huge company like blizzard.
More like God-King *!@#$vald amirite? đŸ˜‚
What about the fight where you have to separate the bosses or it takes forever to kill them? That's really hard to solo unless you're a pet class.