Some additional reasons in favour of saving throws, as well as the very sound ones cited above of agency and involvement:
- The combination of to-hit rolls and saving throws can produce nice subtle probability curves, much better than, say, combining everything into a roll of a single D10 or D20, with modifiers that are a blunt 5/10/20%.
- Splitting the process up into several stages (roll to hit, roll for damage, roll to save) can actually be quicker and easier overall than a single combined roll. This is because whenever you miss, you don’t have to calculate any of the modifiers that apply to the later steps. Thus the total calculation burden and time expenditure can be less.
I’m speaking from the experience of helping Scott Fisher to design “Check Your Six!”, the award-winning and I believe best-selling WWII air combat rules. I successfully argued for successive rolls to hit, to damage, and to save. I’d say the succcess of CY6 suggests this wasn’t a bad decision.
Bloody Big BATTLES!