Willie the Duck
Hero
Fundamentally, attack vs save is one of those legacy things I can't really defend. They changed it in 4e, and likely changed it back mostly in keeping with the recapture the feel of old D&D whenever possible. Fundamentally, for consistency and ease of design, it seems like it makes sense* for either defender or attacker to consistently be the person to roll.
*exception: having them be different allows you the opportunity to make an effect benefit only to-hits and not save-vs, if you actually want something to only benefit some things.
If the goal is a sense (not reality, but sense) of control, I get whey players might like to be the ones rolling (that said, I've played a lot of Symbaroum, which does this, and did not find that it changed the play experience significantly). It means the DM can't fudge rolls*. Tangentially, it also means that if the non-PCs have any limited use re-roll effects or the like, the DM has to declare them in front of the PCs, which might have actual tactical impact.
*which... I don't really recommend most of the time, but can recognize some situations where it might have merit (if someone's 7-year-old wants to play along with the adults, and you want to pull your punches but don't want to tell them that you're pulling your punches)
*exception: having them be different allows you the opportunity to make an effect benefit only to-hits and not save-vs, if you actually want something to only benefit some things.
If the goal is a sense (not reality, but sense) of control, I get whey players might like to be the ones rolling (that said, I've played a lot of Symbaroum, which does this, and did not find that it changed the play experience significantly). It means the DM can't fudge rolls*. Tangentially, it also means that if the non-PCs have any limited use re-roll effects or the like, the DM has to declare them in front of the PCs, which might have actual tactical impact.
*which... I don't really recommend most of the time, but can recognize some situations where it might have merit (if someone's 7-year-old wants to play along with the adults, and you want to pull your punches but don't want to tell them that you're pulling your punches)