On the youtube thing, check here and here.

Also, the Ghosts didn't unlock any Grimoire cards before. Has that changed?

I got the little banner at the bottom of the screen saying we unlocked:

Fallen 4, Vex 4, and Thorn 3.

But neither Uhnn nor Kermit saw the banner, and when I checked the Grimoire there wasn't anything new to read.

That's interesting. Did you check your score before and after? I hadn't heard of them having a banner before the latest update. I imagine that come Tuesday, they'll unlock for everyone that's picked up the Ghosts, but it's possible they might not and we'll need a patch.

Also, the area itself might still exist in Patrol. I think the Undying Mind boss room has remained unchanged since TDB was released, missing killzones and all.

Also, the Ghosts didn't unlock any Grimoire cards before. Has that changed?

I got the little banner at the bottom of the screen saying we unlocked:

Fallen 4, Vex 4, and Thorn 3.

But neither Uhnn nor Kermit saw the banner, and when I checked the Grimoire there wasn't anything new to read.

Getting up there's easy, it's the getting down part that gets interesting. ;)

You can use that area to get below the Patrol area (endless water as far as the eye can see, IIRC) if you make some very careful jumps (or should I say "drops").

Also, the Ghosts didn't unlock any Grimoire cards before. Has that changed?

Until today, when I was tooling around the same part of the Citadel with Kermit. We had almost the exact same conversation and inevitably made our way to the lift and started trying to jump around. It was at this point that we were joined by everyone's good friend Uhnnnnnn and his Titan. We made some progress and it wasn't long before Kermit had a video up explaining where the invisible wall was.

We were figuring it out for a good thirty minutes or so before I was finally able to triple-jump my way up and over the invisible wall and into the lift proper! :D
We were ecstatic, as soon as I reached the top they went to orbit and rejoined on me now in the strange new aerial land of the Vex!

We immediately began exploring the area. Most of the place-space was complete, but there are huge gaps that, presumably, will be filled come next Tuesday. But it was shocking how much of the area was complete and explore-able. All the play area was free to us, and almost all of the non-play area was open as well.

We must have spent two or three hours exploring EVERYTHING. It was awesome, and super cool to know we saw areas that will likely never again be seen by players come Tuesday when all the kill barriers are activated.

Anyway it was a while before I thought to start taking screeshots, but I did. If you'd like to see them, they are down below!

Non-playable geometry.

Most of the non-playable spots were only reachable by some extreme platforming. Like finding tiny nooks you could jump into, from other tiny nooks.

All a bunch of non-playable areas, but really cool looking!

A glimpse of a potential playable area. Kinda think it's fancy set-dressing though.

Dancing on top of that potential area. You can see the primary play space in the background there.

More cool environments.

Unknowable Geometry.

Also got some quick little video clips too.
(Still can't figure out how to embed videos. :( )
Mind the gap.
Fist of Oblivion.
Spotlight Oddity near the bottom of the world.
Ignore the gap.
Triumphant Return.

One of the best parts about it was that we were able to jump/navigate our way down and back into The Juncture. :D

By this time Kermit had already left for a Raid group. Actually he, unfortunately, was gone before I really started thinking about taking photos/videos. :(

All in all it was some of the most fun I've had in Destiny in a long time. Exploring the world in this manner was more along the lines of what I'd hoped exploring Destiny would be like. 10/10 would platform again.

OH! I almost forgot! We found 3 dead ghosts while we were exploring! Didn't post any of the locations cause I personally think it's more fun to find them on your own! But if you'd rather know where they are I'd be happy to tell you.