People may be missing the point. As an all the time spell, it sucks - yes. As a situational spell...it rocks. Prone from grease, ice, etc. = 100%. MM is the only other spell I know that has 100%. Also it ignores line of sight. So:
If you are in the crypt fight and fighting from the little room waiting for all but the last 2 to come to one by one to make the fight simple. While you are waiting, your cleric(s) can be bombing scribes outside the room with a 65% chance to hit.