The invaders' approach to the Tier 1 Objectives should include cover and encouraging choices to the forward position and then to the Objectives themselves. But it also needs to include cover from cross map fire and be free of flanking from the Defender Spawns.
As we discussed in Lesson 11, the approach must include plenty of cover. Too much cover and you wind up with players chasing each other around in circles. Too little cover and the paths become predictable. A happy medium is needed.
Additionally, if you have too little cover, you might find that the Defenders, with precision weapons, can shoot across the map making them too powerful from a single position. A good invasion map will include line of sight blockers to prevent one side of the map from "playing" the other side.
The Alpha and Bravo Defenders on Spire cannot see the others' Invaders approach the others' Objectives due to the rocks through out the middle of the map. Boneyard's Bravo Defenders usually operate out of the bow or lobby of the ship and cannot see any part of the outside, while the Alpha Defenders have very little line of sight on the Bravo Invaders' approach. And the mix of elevations in Breakpoint tends to interfere with cross map fire as well.
Additionally, when Alpha and Bravo Invaders approach their respective Objectives, they move through a forward position and they move on to the Objectives only because they have defeated their corresponding Defenders. That being the case, it can be frustrating for them to approach their Objective and be flanked by newly spawned Defenders.
Boneyard and Breakpoint Defender spawns for Tier 1 are found behind and between the two Objectives. Spire Defender spawns are found directly behind and only slightly outside of their Objectives. In no cases do their spawns sit way off to the side flanking the Invaders' approaches. That is, the Invaders do not have to keep looking over their shoulder to the far side as they make a run for their Objective.
Summary
Tier 1 approaches should include line of sight blockers to prevent Defenders from playing both sides of the map from one position.
Tier 1 Defender Spawns should be directly behind or between the Objectives so that newly spawned Defenders do not naturally flank the Invaders as they make a run for the Objectives.