Theres a ginormous difference.
for 1, on that spot in badlands, the basic scout strategy is to hold your resupply locker while your heavy classes hold the choke to mid by spire to prevent scouts getting behind and to keep a look on whoever might try to flank your medic.
Also every class but the medic can and does get back up there since its the fastest route back to the last lobby from the forward spawn at mid.
Your path is on a totally different level. Its in a room which is closed on 3/4 of its sides so you cant stay there at all, only one team is allowed out of it, and its inaccessible. You could run complete strategies just based off that door. having 3 people charge in rambo style while one holds the door open so they can retreat if needed.
Allowing people to sly behind people without any chance of stopping them prematurely wont work. Imagine a team is trying to cap point 4, and two scouts spawn, the defending team ubers, and the scouts ditch out that door and now can start either a backcap on mid or flank the other team through the main hallway
from a gameplay standpoint it just wont work smoothly.