A Level Map button on the thingie! (bad quality pic, just threw it together).

That new button (the one with three little squares in it, added by me) could bring up the Depth Map. Specifically the depth map only, cause you don't want more buttons to press etc. When you're just checking the map (just like the area map - a split-second peek). The depth map could be a bit transparent, too, to fit into the sorta...overlay type deal along with the area map. Like we're looking at ourselves through Iron Man's J.a.r.v.i.s (but still top-down, GAME LOGIC! YAY!) with all the infos. Yet I also support the option to completely remove everything from the HUD (HP, shield, team, everything) and game risky-style, but that's another topic.

Very useful for quick checks in arcade, and just fun in rank/expansion/pr missions.

The tiny, tiny little (center) connective line in the button could change when the next level of the gate you're in changes. That would be neat! It would just swap positions, and that's your notification. If you know what level is next, and you want it, and you see the square connection line flip/mirror itself in the little button, but you're not by the elevator, hurry!

Inspired by: the map toggle button.

Note:
If you click this button in Haven (or guild halls/places without depths to go to - even in the "haven arcade"), it simply brings up the Arcade interface (that many players get to by getting to the Missions interface, and pressing that "arcade" button with a fiend on it). Or the missions interface (but there's already a button for that on the side of the screen, so I vote arcade shortcut). Or it could just disappear in areas that don't have depth maps/elevators, like the zoom button disappears when you're in an area that doesn't really have that option.