I don't see putting the wizards to sleep for the duration of their sentence as at all inhumane, just very ineffective punishment.
Perhaps not as effective as current punishments, but being Rip Van Winkle is still a bad situation to be in - especially if it's intended as a punishment, as then not much will be done to help you!
Help in what sense? It wouldn't be much use as far as rehabilitation goes, but neither are most prisons, and Azkaban is certainly worse. In terms of visitations or breakout attempts, what would be the point?
Update: Discussion has moved on to a new thread.
After 61 chapters of Harry Potter and the Methods of Rationality and 5 discussion threads with over 500 comments each, HPMOR discussion has graduated from the main page and moved into the Less Wrong discussion section (which seems like a more appropriate location). You can post all of your insights, speculation, and, well, discussion about Eliezer Yudkowsky's Harry Potter fanfic here.
Previous threads are available under the harry_potter tag on the main page (or: one, two, three, four, five); this and future threads will be found under the discussion section tag (since there is a separate tag system for the discussion section). See also the author page for (almost) all things HPMOR, and AdeleneDawner's Author's Notes archive for one thing that the author page is missing.
As a reminder, it's useful to indicate at the start of your comment which chapter you are commenting on. Time passes but your comment stays the same.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: