My $0.02 on daypacks for a backpack trip is, there really is no downside to using a good full-sized internal frame pack with cinch straps for the same purpose. And the upside is, you always have a full-sized pack with you so there are no trips back to camp for your meat hauler.
A full-sized pack weighs more for day hunts but with a light load it really doesn't matter and the extra weight on a day hunt is offset by the weight savings of not packing an extra pack with your full load.
