J-H
Hero
That works pretty well, but I'm concerned about the interaction with AC. Taking my drow warriors up-thread as an example (with +2 plate/+3 shield and 25 AC), a +10 gives them a 35 AC, making them immune to any spell attack that's not a natural 20 (natural character max is +15 to hit with a tome and a +3 item at level 20). That seems a bit much, and it's going to make high-AC enemies such as dragons outright immune instead of resistant.