Why do were doors removed in the maps? Thread - Base Defense mod for Half-Life

I'm kind of curious as to why the doors were removed in the new update.

They were made to make some parts of the map needed to be unlocked, but it looks like tomb and building don't have a space for this. Doors on those maps were just a way to hide from monsters or to make them stuck, this is not what they are meant to be, so doors work like they should only for boss rooms.

I believe some mappers can use priced doors in more interesting ways.