Cadfan said:A reroll is equally powerful regardless of character level.
Very true. One thing we've gotten used to with 3.5 is the idea that spell effectiveness increases level by level, relative to opponents at the same level. At 3rd level, an opponent who fails a Fort save against your spell is blinded; at 13th level, an opponent who fails a Fort save against your spell drops dead.
This seems natural at first, and helps create the sense of progress as you gain levels--you're not just increasing your numbers, you're doing cooler stuff. Unfortunately, it also inevitably leads to the high-level uber-wizard... because the wizard is getting more and more powerful relative to his opponents at each level. Ten or twelve levels of that and you can't help but be overpowered.
(It's worth noting that editions before 3E had a solution to this problem. All saving throws were fixed difficulty--whether you were a 1st-level wizard or a 20th-level one, it didn't get any harder to save against your spells. High-level monsters had better saving throws, so the increased effect was compensated for by the decreased chance of success. Unfortunately, this makes the game increasingly "swingy" at high levels and has verisimilitude issues.)
4th Edition has clearly recognized this. Consequently, I don't think we're going to see much of the old "bigger status effect" approach to magic. Spells will do more damage, commensurate with monsters' higher hit points, but if a 1st-level spell dazes one monster for one round, you won't see a 20th-level spell that dazes ten monsters for ten rounds. The sense of progress will largely result from increased tactical options--fly and the like.