A lot of bombers are flown by new players (my observation at least). If level bombing will become too difficult, or even a little difficult, bombers will be used to dive bomb. We have been there before. If some mechanic is to be enforced to lower accuracy, bomb release from F3 view and at steep angles should be disabled as well to prevent dive bombing with the heavies.
The problem in terms of gameplay is not the absolute accuracy, but the accuracy for very high alts. A bomber that takes the time to climb to 30k is nearly guaranteed to hit his target. This is how porking of ammo/dar/troops is easily done across the front. No defender wastes his time to patrol at 30k in the hope of running into a random bomber formation, except perhaps near the big strats when close to the front. Random furballers will not have the time to climb and catch it when starting when the bombers are spotted and announced on range channel. So for bombers, success is just a matter of (boring) time investment. Bringing in the bombers at 20k or less requires coordination with fighter escorts/sweepers or large formations. New players do not do that and neither most of the experienced ones.
The problem with the wind sheer suggestion is that the way it is implemented in AH is a step function. When crossing the boundary, the airspeed instantly jumps by XXX mph, which is not good. If a wind layer is to be implemented, the speed needs to be built up gradually over a couple of kft. The other problem is that a static wind direction becomes an advantage to the country that is upwind, thus affecting map balance.
I see the solution somewhere in the realm of accuracy. I dont mind if a righteous bombardier can drop his bomb through the eye of a needle from 15k - I do mind when he can still do it from 25+ kft up.