I don't know... (I mean I believe you, but maybe you have been relying on the DC all this time?)
I mean, I bought the game about 40 days ago.. and I had trouble going through the slot with my sidewinder at first, even mentioned it in a couple of my posts
And yes, I thought the slot is way too small, but compared to when I started I'm now always boosting with my Python after I take off (and it has a boost speed of 500...) and have no problem going through the slot.
When I bought the Anaconda, I was constantly scraping / hitting the side of the slot with the bottom.. so I loitered there for a few seconds to turn on the camera mode and check what my ship is actually doing.. I realized that due to the deck being way on top and literally nothing above that, you simply need to aim it as though you're planning on bumping your head into the ceiling and it goes through every time without hitting it.
What I'm trying to say is that imo. you simply need to remember how each ship handles and if you know where to aim it, it goes through every time.. I even advanced to the point where I'm actually pulling to the green side so tightly that 2 other Anacondas would fit through next to me.. so I'm actually enjoying that slot I hated so much at the beginning
That barbecue grate on the outside though.. that's just ugly and annoying imo, dunno who put that there... Also I only wish they increased the speed limit a bit.. to maybe like 150 so