Well, OK, more connected worlds. Lets have proper insides to the buildings and connected cave systems.

In a sense there would be three connected play spaces: outdoors, inside buildings, cave systems. But you could see into the other play spaces from each one. Connected.

Buildings

It's a bit weak/lazy to have monster closets scattered around the periphery of buildings. Give us proper buildings with corridors and rooms either side of said corridors with views out of the windows.

Show enemies leaving drop ships and entering buildings. Have enemies enter buildings via roof tops.

I want to think that enemies aren't spawning in monster closets.

I'd just like the world to be more believable - not so obviously contrived.

If memory serves, HL2 had convincing buildings. I think they had architects on staff. Maybe Bungie does too but the buildings still just look like connected play spaces. I don't get the sense that they are real buildings.

Halo was more of a real place to me, even with the fantastic SF elements. Destiny is just too false and obviously gamey (in a bad way). The real world doesn't have buildings that are solid blocks with monster closets carved into their sides.

Caves

With caves have vertical drops into them that enemies come down - like wot we saw in the Halo rooms in the original Halo. You could imagine Flood dropping into the rooms via them but you couldn't get up them yourself.

I like that area on the moon where a bunch of fallen boulders make a cave system. The newer hardware must be able to handle more complicated geometry.

Again, if we see enemies enter cave systems then we can buy seeing enemies leave them (we don't think, "I bet they are just spawning in there")