I have some reservations here. (FalloutJack plus one? Ta'.) First, I'll just say it. No, I have never rooted for a troll. With that out of the way, I'd like to get down to some other things I have to say on the subject, in the spirit of the discussion.
First, trolls aren't what I call the ultimate bad guy. They're goblins in Baldur's Gate, Gremlins in...all media, and more or less Yahtzee's imps (to make a more Escapist-like reference.) I don't see anything powerful or stylish in terms of evil here, and I like to think I know a few things about villainy. Being the guy who dangles a key to your cell just out of reach isn't ultimate anything, except annoying. And annoyances...well...they get munched, fairly quickly. They're a tedious game obstacle, not a boss, unless of course you mean a legitimate fantasy troll with a big clobbermeister. If not, then sorry, I don't agree.
And I don't find them very clever either. For one, to borrow from a meme, obvious troll is obvious. They ain't bright, which is one of the reasons they're even called trolls. A 'clever troll' is just what I call a different flavor of asshole, which is a whole new genus and species, you could say. Why do I say they can't be clever? Well, I've outed so many without being offensive or breaking any rules, myself, which leads them to be hit with a banhammer (true story) and I walk away with the knowledge that the board will be better off by some miniscule fractional amount.
They aren't actually harmful, which is why when trolls go looking to be fed...I, well...eat them instead. It is, however, not a very healthy diet. The act of it certainly does swell the ego in direct proportion to how much of an idiot said troll actually was. So, I've had to be rather careful with it.
I'm sorry, I appear to have been thrown into a rant here. Can someone shout "Exalted!" so I can get back on track?