One of my players made a character who's a 2ft. tall gnome artificer. He just created a bag of holding as his wondrous invention, but the exterior dimensions (2ft. wide by 4ft. deep) is bigger than him. So I decide to make it a drawstring backpack with a 2ft. mouth so he still has the same insertion dimensions, and 1.5ft. deep so he can wear it like a backpack and not trip.
Does this change anything about the bag mechanically? Does this seem like a reasonable change?