Do you only play with poorly geared BLMs and SCHs? There is no way Spiritreaver is competing with SCH. BLM, sure, but not SCH. Here's the numbers I just ran on a neutral day on Ul'hpemdes:
3685 - Blizzard V (Ebullience, Klimaform, Hailstorm w/ 5/5 Stormsurge merits)
3786 - Thunder V (Ebullience, Klimaform, Thunderstorm)
Keep in mind that these numbers aren't even the best SCH can do, since I've only managed to upgrade my staves and my hat since the 90 cap. Also, I used Moldavite instead of Hecate's to ensure I wasn't getting m.crits. Messing around with day+weather bonus, I was seeing numbers like 3927 and 4221 for Blizzard V and Thunder V respectively (some combination of Moldavite/Hecate's/Novio).
My BLM damage for comparison:
3079 - Blizzard V (Hailstorm)
Mercilessturtle's Bobeche (also hasn't upgraded gear since the 90 cap):
3414 - Thunder V
So no, PUP is not competing with SCH in terms of damage. Hateless damage? Sure. But not raw damage.