[Blackwolf]

That ravine looked pretty impassible to me. In the 2 hour beta streams with Higby, they fought around that bridge trying to take the base that over looks it from the VS. There was only narrow passage that lead up the ravine on the east side that lead towards the VS base. On foot and in a vehicle, that terrain is a nightmare and it can be hard to see that without actually being there.

That ravine is very big, something that is lost in TB's video because he spends more of his time flying around the area and not walking around it.

The bridge itself has a support structure underneath it that you can get into and shoot at people in the ravine from. It's also wide enough for 2 Vanguards to drive down side by side, possibly 3, and still plenty of room for infantry to take cover and take shots at said Vanguards. In addition to the underside of the bridge, you have the top side which you can get to with jump packs or possibly on foot, allowing you to shoot down at those crossing the bridge. The bridge in that scene also provides excellent cover for snipers hitting the ridgeline around the nearby base, which itself is a very tough base to take because it involves a steep climb around a bend through a narrow passage that is easily defensible.