I really disliked the dungeon journal in WoW and always thought it was a bad idea. It took a lot of fun out of learning new bosses when they were released as you already knew what to expect. Even if was locked away for a few weeks, people will still datamine the information.

If someone wants to look up a guide for old content, there are plenty of them posted on YouTube and other websites.

Also having the map already available for the Variant Dungeon takes away a lot of the fun with trying to figure out how to fully complete the thing, especially with the final secret.