Hate to admit, but more than half of the time on horse I'm using Longsword in 1H mode with shield, and the sword lasts much longer before it breaks even though half the time it is in 1H mode.
Only time it's 2H mode would be when I'm dismounted or fighting another 2H cav. The manual blocking and dueling on horseback maneuvering back and forth, it's much more exciting than on the ground, much cooler, too.
So if OP's suggestion is implemented, it's going to be a hassle for me since I always manually repair my items.