Could this have been Joss doing Return of the Jedi the way it was meant to be done?
Let's take a moment to consider parallels: Act I & New Hope, Act II & Empire. Dramatic dark shift in tone? Check. Resoundingly compelling wrinkles added to the principal characters at the end? Check. Simultaneous broadening and narrowing of focus? Check and check.
I've read my fair share of literature/fan articles regarding Star Wars over the course of my life, and while this is not the first place I came across information regarding the way ROTJ could've gone, it has the dual distinction of being 1) the first real source I came across while blindly stumbling through Google and 2) actually, a pretty neat little article ("little?"), and actually worth the time it takes to read, if you're a fanatic (like me!). What's important are the ways in which the movie that made its way to the silver screen differed from initial ideas, which were lighter on that special, trademarked brand of George Lucas magic.
First and foremost, Harrison Ford wanted out. He didn't want to do a third movie, so he pushed hard for Han to die in the carbonite. Obviously, he didn't get his way, which left us open for such heartwarming moments as, "I think my eyes are getting better. Before, I could only see a big dark blur, and now I see a big light blur," and the protect-and-grope maneuver he pulls off just after Carrie Fisher's Princess Leia gets shot by the stormtroopers. Star Wars sans Han Solo almost happened...
Secondly (and I'm pretty sure this is an idea with its roots in the Kurosawa movies that served as so much inspiration for the George Lucas money-printing machine), the explicit restatement of the hero as an entity forced to separate from society. Obi-Wan and Yoda were both good examples of this, but they both existed (in the original trilogy) as examples for Luke to follow/live up to, not as the sort of warrior monk that Luke became by ROTJ. The way I heard it, an idea was pitched that Luke, after departing the now-destroyed Death Star II, was so adversely affected by his crusade to save the galaxy that he could no longer be a part of the world he fought so dearly to protect, and as a result, had to disappear, just like Alan Ladd in Shane, or the ronin in Seven Samurai (other real film critics have so dissected the relationship between American westerns and Japanese samurai movies so thoroughly that I really have no cause to do so myself). Again, that's not remotely close to what happened.
The reason I bring all of this up in my reaction to the third act of Dr. Horrible is that, while ROTJ feels almost compromised, as though an honest, more natural progression was supplanted by something easier to sell, and easier for an audience to stomach (this probably marked the turning point from Lucas the "artist" to Lucas the businessman - in case that point hasn't gotten driven home enough yet, here you go), Act III of Dr. Horrible allows none of its characters, nor its story, to take the easy way out (well, maybe Captain Hammer, but that's just because he's a superhero in the truest sense of the word - he's an adolescent boy living out his power fantasy as an adult male). As Billy/Dr. Horrible/Neil Patrick Harris/Doogie Howser falls further and further away from the light, we're with him every terrible, horrible step of the way.
Since this is a Joss Whedon production, it's worth taking a moment or two to consider Penny, and how she might function more like a device than any other female character in his work that I can recall. Penny doesn't really have much of an arc (she starts off nice and sweet, and ends up nice, and sweet, and dead), but I don't think she's necessarily supposed to. What she is supposed to do - what she does well - is serve as a point of idealization for Dr. Horrible/Billy, and as a point of contention between the Doc and Captain Hammer. Her development is limited, her scope is limited, but then again... this whole endavour was barely as long as an hour-long episode of a television show. It's frankly incredible that they packed as much into this project as they did.
Hearing Penny mumble, "Captain Hammer will save us," as she lay on the ground, pierced by the shards of Dr. Horrible's weapon, the life leaking out of her body, was nearly as affecting as the moment Fillion's Malcolm Reynolds told Simon Tam that the ever-lovable Kaylee Fry had expired on his operating table (the moment at which I knew Firefly could do anything that came to its mind and I would follow it to the ends of the earth) - I nearly felt as devestated as the character onscreen.
Fillion, as always, does a remarkable job. Lacking the strongest singing voice in history, he manages to sell his "Everyone's a Hero" number quite effectively, getting away with it through gumption, perservance and sheer charisma (really, the way he pulls all of his parts off). And no one plays pain better than Nathan Fillion (see "Out of Gas" and Serenity for more information).
Now is as good a time as any, I suppose, to go into the broadening of the series' focus in the last act. With the introduction of people on the streeet, everyday citizens whose lives are affected directly by the actions of these heroes and villains, the scope of the show becomes much bigger. No longer do our characters operate in a vacuum - the Captain has discovered a new avenue of superheroism, one that involves picking people up at least as much as it does knocking them down, and we finally see the ramifications of the cartoonish supervillainy (as Waylon Smithers might've called it) that Dr. Horrible wants so dearly to practice. There is now a world that responds to the actions of our characters, one that will shun them both by the end (expect, perhaps, for the Captain Hammer fan club, which could give Joss fodder for seasons worth of television all by themselves).
Clearly, Dr. Horrible had put Penny on some kind of pedestal. Would he have given up his life of crime for her, and maybe even taken up the banner of gradual, unassuming social change that she waved so passionately? We'll never know that, but what we do discover is that she was the last little magnetic speck tugging at his moral compass. When she expired, she took along with her that last little nagging sense of right and wrong that lived in the back of his mind. Much like Captan Hammer, at the end, Dr. Horrible is a broken man, an empty man that has nothing but his "work" left to sustain him.
The design of his costume at the end is fantastic, by the way. Serious kudos to the person who came up with that.
To bring this back around, at the end of the series, our hero (the villain) removes himself from society. He knows he's dangerous to be around; nothing makes that more clear than his inadvertent party to Penny's death. The best he can do is associate with those that are equally dangerous, if not more so. Hence, the Evil League of Evil.
A pretty successful experiment, all things considered. I hope they've managed to generate some revenue with the new distribution model, but I'm not so sure it's a harbinger of things to come. If I'd put out Dr. Horrible's Sing-Along Blog, no one would've paid for it. I'm not Joss Whedon, I didn't create fucking Firefly, Angel, Buffy. Just like Trent with his self-distributed music, Joss has a dedicated audience already. They can make the initial purchases, they can spread the word. A less-beloved, less-well-known creator would be unable to make the same splashes.
But, still, it was awesome.