The depth charges .zon file I once tried increasing the damage radius to make evasion more challenging, but the silly lubbers were always wrecking their own racks so were limited to one attack each.
As for 1.5, tried it for a few months, went back to 1.4. Aside from Das Boot the main difference I saw was 1.4 works fine most of the time, crashes occasionally. 1.5 crashed most of the time, worked as often as government employees.