The problem would be that the item acquisition is part of the problem. A level 10 item is often far more interesting than a level 11 item which I guess is somewhat unfortunate. But make the difference +2 to hit and it would be necessary for characters to update their weapons to the next level as fast as they can. This leads to magic weapons taking up a disproportional percentage of treasure parcels. Moreover it makes attack bonus scaling even less linear. The main issue hear is to make attack bonus advancement fit monster defense advancement and the latter is relatively linear (absolutely linear if the DMG rules are followed actually).