TL;DR
Giving a hitbox to robots (bots will not move through themselves) and a load/unload time will increase the challenge of the game and make the robot logistic system less OP. (better think twice where change from belts to bots)What ?
HITBOX: the drones will not just move to chest, load, and run to destination, they have to pay attention to other bots and not collide with other flying objects (so no more 200 drones all packed together in 1 tile). This will create a sort of "2lanes flying highway" between chests.CARGOTIME: with a load/unload time, move tons of items will need more infrastructure planning: more passive chest and more requester in the same locations, and then inserters or belts to merge everything together