Busy week and only just got around to this. Took your formula and in place of .05 added a rule to the DB. End result is that for every 1 you add to the DB value, min hit will increase by weapon damage x level as a percentage.
Using a 140/20 2h weapon:
DB Value of 0: 893 dps (current state)
DB Value of 1: 994 dps (+10% dps)
..
DB value of 5 (as per your theoretical suggestion

Would expect it to be pretty flat across different weapons, so seems like a viable alternative to damage bonus.