LostSoul
Adventurer
Yes, necessarily. I asked this on Twitter, and Mearls said that in a "target determines DC" system, the chance to resist would be the same.
I know this is how 1e and 2e did it, but it seems odd to me after all these years. I then asked if this idea could be coupled with 4e's "DC by level" table, with columns for Easy, Average and Hard for more variance.
I have a theory about what's changed over the years. I think that saving throws were made when you were about to take some kind of effect that you could not avoid - there's no dodging a fireball, for example. You make a saving throw to see how lucky you got (or how much divine intervention you receive, or if your magical powers allow you to resist the spell, or if you can just tough it out, or whatever).
If you could avoid the effect then you wouldn't need to make a saving throw.
In that system there's no reason for the save from a 1st-level wizard's cause fear to be harder than a 20th-level lich's. The fear - from either source - is not something you can avoid; you are terrified, now let's make a save to see if you can luck out of it somehow. (I think that's why they have the HD limits on spells, too.)
These days you can dodge fireballs and shake off ghoul paralysis, and you make a saving throw to see if you do or not.