And thats where you are wrong.
This would solve the problem you think it would create.
Benos don't care about preserving their numbers - Benos are allowed to be more suicidal - In spirit of the lore (if any loser cares) and fun for both sides as benos get to be mindless again and marines get to kill those few who truly go mindless.
Promoting dumb flanks - Larvae surge already does that, no post-evac fights = no larvae surge = no reason for dumb flanks. So at the end, its the same.
Lowering marine numbers - Benos don't have to care about that, which is fine, if they don't care about killing marines, they lose, simple.
They just have to rush a undefended FOB flank and tunnel queen there - I see this as win - win situation. Marines have to defend every side and there is finite number of such flanks on every map.
Overall, removing post-evac fight would solve most of the issues. No meta-evac, it would be simply impossible. If you do that, you just lose the chance to fight, so you might as well not deploy in the first place and benos win. Marines would fight groundside to death.
No "unfair" systems, no cancer larvae surges etc.
But we all know that Almayer fights will never be removed. For those who are afraid that their favourite meat grinder could be removed, I have great news. Council of Beetroot got your back.
Thats why somebody has to came up with alternative, patch, or fix to larvae surge.
I got an idea for something like that. Create a room in Almayer that is fairly difficult to hold (that DS can't crash into), but rewards it. For example, if marines are able to hold this spot for 7.5 minutes after DS crashes, crashed DS simply flies BACK planetside, turns off larvae surge and deletes rest of the burrowed/pooled laraves (the trick being that benos shouldn't be allowed to relocate spawn pool from that spot).
And here you got it. ARES core seems like a perfect candidate for such "room", because its fairly hard to hold (not much free space around to move like brieffing, away from Req, or medbay, makes sense in game that ARES could do something like that and can be sieged from every side, benos just need to destroy weak walls).
Makes that mariens have atleast 2 options, either rush DS ASAP, or hold for a while. More options is good, don't listen to the devs.
And bang, pretty good if I have to say so myself.
Also don't try to bullshit "muh lore/logic/sense" with crashed DS being able to fly again.
First: HEFA Order is canon.
Second: In game that is canon (Aliens: Colonial Marines), DS crashes into a ship and then flies back after a while.
For bonus meme points don't allow Queen to ovi anywhere on the ship but crashed DS cockpit.