TL;DR:
The reason Rush sucked in BF1, BF4 is present in BFV again. The reason are map boundaries.
BF3 Boundaries:
https://i.imgur.com/ln6yymt.jpg
https://i.imgur.com/ohDlAlR.png
In general, MCOMs at the FAR side of the map for attackers, several possibles lines of defense for defenders until they reach the MCOMs. Phases are more open, i.e. more squares or rectangles then just lines, allowing for more maneuvering and flanking. Attackers can flank defenders in the first few lines of defense, or Defenders can flank and push back attackers when they're on the last line. Of course there are some exceptions, especially on Metro. But this is in general.
BF4/BFV boundaries:
https://i.imgur.com/SoPF9uk.jpg
https://i.imgur.com/E25DX7g.jpg (Attackers come from NORTH)
MCOMs immediately at the edge of the CLOSE side of the map to the attackers; essentially just 1 line of defense for defenders. You don't defend 1 push, you lose the phase. Almost no room at all for maneuvering or flanking for either team. Again, a generalization, of course there's some exceptions.
Before anyone says it, I know - in BC2 and BF3, the maps were designed around Rush. That's why it was so insanely good in those games. The maps in BF4 & BF1 are designed for Conquest. But that's only part of the reason Rush was so awful it was barely playable in them.
In addition to just having maps in general that don't support structured game modes like Rush, they had the issue of absolutely atrocious map boundaries for each phase. This was far more of an issue than the maps not being designed for Rush specifically.
And BFV has it again.
Look at the first two phases of Twisted Steel Rush.
The very first phase, the map boundaries for the defender are a literal line. It's like 10m of actual playable area from the MCOM you defend to the out of bounds to attacker spawn. There is absolutely no way to flank or outmaneuvre the enemy at all. And the same of course applies for the attacker. If you try to flank through under the bridge, you're literally in open view to the defender spawn, which of course is also completely out of bound for you.
There's nothing either team can really do in this phase, except blob and hope your team outspams the enemy team. And the attackers have a Tank who is outside map boundaries for defenders. Couple that with the fact that, again the MCOMs are IMMEDIATELY at the edge of the map boundary to the attacker spawn, and I think we can see who is gonna win this phase 99% of the time.
The second phase is again very similar. The MCOMs are immediately at the map boundary towards the attacker spawn for the defenders. But this time, that's not the entire playable area for the defenders: 3/4 of the map boundaries for defenders are behind the MCOMs. This area is utterly and completely useless, you can't do anything from there. Oh, right. Except foil any attackers attempt at flanking. Because if you go here, you can see past the right of the building complex in a direct line to enemy spawn.
What this means is that again, the attackers only real option is a direct frontal assault on the MCOMs.
So it's just a blobfest of defender vs attacker again, until attackers get enough kills to make literally ONE push and then it's their phase again because the MCOMs are directly located at the defender's first line of defense.
Basically, in BF4/BF1/BFV Rush, the defenders can't fall back 5m without immediately conceding the MCOMs to the attacker. The MCOMs are facing TOWARDS the attacker spawn, not towards your own spawn.
Now, let's compare it to BF3 Rush, example map damavand peak:
https://i.imgur.com/ln6yymt.jpg
What is the first thing we immediately notice?
The MCOMs are located at the BACK of each phase, not at the front. The defenders have several lines of defense where they can fall back if need be, until they end up at the MCOMs. And the play areas in general are big enough or have enough routes and cover that flanking is a possiblity. While this wouldn't be possible on all BF1/4/V maps due to them not being designed for Rush, it'd certainly be possible on some maps if the boundaries and location of each phase was better.
External link →