That wouldn't make any sense- by doing so he loses a lot of followers (Bellatrix at least was imprisoned), allows the enemy to regroup, and would make them more hopeful of winning the next time. (Who's going to believe him, after all?)
Probably any of the Death Eaters. If you were Voldemort, would you leave yourself without a way to identify yourself to your followers whatever shape you happened to be in at the time? As for the followers who were imprisoned, remember that if canon is anything to go by, when he's prepared to reveal himself, Voldemort could break everyone out of Azkaban.
His enemies aren't just recuperated, they're complacent. Do you think Voldemort could have gotten this close to Dumbledore while the war was on?
Far from making them more hopeful of winning, if he pulled of...
- This thread has run its course. You will find newer threads in the discussion section.
Another discussion thread - the fourth - has reached the (arbitrary?) 500 comments threshold, so it's time for a new thread for Eliezer Yudkowsky's widely-praised Harry Potter fanfic.
Most of the paratext and fan-made resources are listed on Mr. LessWrong's author page. There is also AdeleneDawner's collection of most of the previously-published Author's Notes.
Older threads: one, two, three, four. By tag.
Newer threads are in the Discussion section, starting from Part 6.
Spoiler policy as suggested by Unnamed and approved by Eliezer, me, and at least three other upmodders:
It would also be quite sensible and welcome to continue the practice of declaring at the top of your post which chapters you are about to discuss, especially for newly-published ones, so that people who haven't yet seen them can stop reading in time.