I found an article talking about the worst power-ups. Sleep magic was on the list. Would you agree with this? I'll post my opinion later.
http://www.1up.com/do/feature?pager.offset=1&cId=3167284
No matter the RPG, there's usually a type of magic that someone, somewhere still insists is useful. Whether it's called "grey magic," "status magic," or "that bunch of spells you can safely ignore," this special brand of monster-weakening arcana has been completely worthless throughout most of RPG history. Some games, like Final Fantasy XII, have bucked this trend by making status magic extremely useful, if not mandatory -- but Square's franchise-redefining RPG is really the exception to the rule. In nearly everything else, though, the option to weaken creatures instead of blowing them up only prolongs the inevitable -- and nothing does this better than the all-purpose sleep spell.
The main problem with sleep magic and its ilk is that if a game provided situations where such spells were actually useful, it would be more boring than public television. Think about it: If you play RPGs -- especially those of the traditional, random-encounter variety -- do you honestly want whatever you're fighting to still be standing after more than two attacks? That's the problem with sleep magic: Anything you fight is inevitably going to die, so why does it need a nap before going off to that great monster closet in the sky? The only battles that could benefit from sleep magic, and status magic in general, are boss battles, but there's a certain cost that comes with making bosses susceptible to ailments: It robs the reward from of any victory -- and we've all experienced that shameful, empty feeling that comes with the instant demise of some undead horror after casting "life" or throwing a Phoenix Down at them. Until sleep magic lets us knock out greedy shopkeepers who would dare charge the saviors of the world for potions, using it will be as futile and unfulfilling as trying to dissect the plot of the Xenosaga series.
http://www.1up.com/do/feature?pager.offset=1&cId=3167284