Great, table based dungeon design. So that the chain of 10ft. rooms with orcs and chests the players have to go through makes even less sense.
You already have plenty of replies here, but I do get your comment. It really felt like Keep on the Shadowfell was created using something like this, and with those 10' rooms made into 20' rooms.
On the other hand, tables like these are actually quite good to get your imagination going. It's a good way of saying what monsters would logically group together, and the ration between them.
If they also write a page or two on how the dungeons should be layed out to make some sense, avoiding bunching rooms too close together (if you don't want all the monsters to join a fight), it's probably enough to create an interesting dungeon crawl. Sure, if you aren't into dungeon crawls, it won't help, but it could teach new DM's the basics of adventure design.
As it currently look, 5e looks to be relatively lean when it comes to rules, so instead of filling the books with rules, they fill them with content that help a DM create and run adventures/campaigns. Probably a lot more inspiring than the 4e crunch books that were as interesting to read as an inventory list.