It wouldn't work with my load, which is why it is the way it is. Most days I'm rolling out with a bricked out 1000. My biggest bulk stop gets a lot of pretty big air pieces. If they tried to load them up front, I would still have to unload it all to verify it. And it would make it more difficult to get to any other airs that I would need to deliver before that stop. Most days I have to leave that stop until just before 1030 so I can get all the air off on time. And it's not the only bulk air stop I have. I almost never have issues with missing air, though I do get other people's air loaded in there sometimes.
If I just had a handful of envelopes to flip through, then yes, it wouldn't be an issue to load it all on the 1000 shelf and verify it.