Errol Le Cain
Lit.Scribbles has a very interesting post called The Twelve Dancing Princesses and the Politics of Taking Pictures. Follow the link to see what taking pictures has to do with the fairy tale; but the author expresses her distaste for the Soldier/hero of the tale because he is rewarded for doing nothing; the old woman tells him what to do, and all he does is creepily stalk the Princesses for three nights in a row.
The above post brings out some very good points which I hadn't considered before. But I thought about why I had never thought of the Soldier in that light, and I came up with a few reasons:
1. I think most people sort of assume that the Soldier in question is already a Good Man and that that's why the old woman chooses him, out of all the other men eager to take the King's offer. You COULD go so far as to say that, since he was not one of the first men to go and try his luck, he is perhaps showing wisdom in waiting to learn more. But I admit that's kind of a stretch.
2. The Soldier doesn't really do nothing: he follows the old woman's instructions. And following instructions is pretty hard for fairy tale characters. In fact, his main virtue is obedience. Ah, that word that gets modern females all worked up when applied to females, but here is an example of a male getting rewarded for obedience, typically thought to be the main virtue looked for in a woman. So, that's actually pretty awesome.
Now, as for the creepiness, most versions try to hint that the Soldier is feigning sleep while the Princesses change and only watches them once they have checked on him to make sure he's sleeping. I think most readers/hearers of the tale just get excited at the sneaking around invisibly, and at the mystery he's solving, and don't really think of it as stalking 12 women. Although the history of fairy tales certainly does involve a lot more sexual innuendo than in the versions we're most familiar with today, so I guess each reader can infer what they want to.
But I do agree that I don't see why the secret kingdom is so evil. The reason the tale is so popular is because every girl (and possibly boy) wishes she had a secret door in her room that led to a magical kingdom, whether or not dancing all night would be their dream scenario. The most negative consequence is the worn out shoes, but the Princesses don't seem to be tired. (Did the King ever try just...not replacing their shoes? That would have solved his money problem at least.) Other versions will try to describe an evil spell to make the destroying of the Kingdom more satisfying. But I think the reason hearers aren't too disappointed when the Kingdom is exposed and destroyed is that for us, the hearers, we know the Kingdom will always be there, our own secret and our own discovery at the same time, every time we revisit the tale.