One thing that seems to have been missed here is that without retardation there is a serious real risk that a bomb dropped at very low level will bounce up and destroy the dropping aircraft even with a fuse delay. In real life, breaking immediately after release didn't guarantee safe passage as the bomb didn't always bounce straight.
So overall, I feel that the existing risk in AH of fragging yourself with your own ordnance when releasing at very low level (assuming the bomb travels at least 1000ft after release) is a reasonable simulation of the real time risks.
Btw, as I understand it, fuse delays were set for various reasons. Sometimes just to allow the bomber to clear the blast area, sometimes to make bomb clearance more hazardous. (Delayed action.) I think the delay built-in to bombs like the Tallboy wasn't connected to the arming fuse itself, but to an inertia switch that sensed the actual impact and fired the detonator about half a second later after the bomb had penetrated the concrete.