They didn't "remove" AO, it just probably has a LOD or is not being used in the spectator mode (where that image is from). You can easily spot AO in the gameplay segments of every video.
Quick and dirty example
I don't know.. There are hints of occlusion on static geometry, where they are probably baking it, and beneath the destroyable objects but not on the ground that they are touching.
From Gamerysde: (click to enlarge)
You can see occlusion behind the pipes, that are static. You cannot see occlusion on the ground beneath the sacks that are ready to explode, only darkening on the sacks themselves. No character occlusion on characters, that I know for sure they used on TLoU single player, not sure about the multi. No AO underneath rocks.
A) AO for static geometry
B) No AO on character
C) No Character contact shadows on world geometry
D) No AO under dynamic objects (Those look like flying, but they are not)
E) Sacks have a darkened lining at the bottom, which doesn’t match the ground.
They seem to be destructible, after all. But the faked / baked AO doesn’t match the ground
which seems to show a small hint of low frequency AO (probably baked, as destroyed sacks
may not be vanishing completely after being blown up but could be leaving parts on ground.
Disclaimer: I hate haloing AO as much as the next guy, better without it than with, but I really liked character AO (contact shadows for characters) on TLoU for example.. I like AO when it's subtle, but just wanting to point out the scaling back of the MP and I find Battlefront's visuals above the Uncharted Multi, whether because of asset creation or rendering tech.
Edit: Just checked, TLoU employs character contact shadows on world geometry for both the player and the opponents in multiplayer, but it seems to be missing here. Edit: I guess contact shadows isn't entirely gone, but it may be a thing with the LOD and characters other than the player.