I'm glad that Mojang won this contest, to me playing it has been the most fun that I've had playing a video game in years. But that is not to say that I automatically hate Bioware, Valve, etc. Quite the opposite actually. Bioware is the best at RPG's in my opinion, and what Valve has done with Steam and their games is great for the industry as well.
But my reason for picking MC even if it isn't finished is because of how different it is in an industry where let's face it pretty much every game made is very similar to another in it's genre, portal standing out as a very good exception. Bioware makes excellent RPGs, I loved DA 1 and only heard good things about Mass Effect, but here is the point I get hung up on, DA and ME while great are still RPG's on rails to a wide scope yes, but there is a fixed plot that you will eventually complete, just like every other RPG made. Even taking Oblivion into account, it's a sandbox, but it's an empty sandbox where nothing that you do unless you're using an editor actually changes the world. The plot goes on, you have your little side quests but in effect the world at the end will always be pretty much the same regardless of your choices in it.
Which brings me back to MC, it's completely open ended, a lot of people on the forums have used it's lack of story as a negative, to me that's the biggest positive about it. Playing the game isn't some writers story, it's MY story, and when done with friends it's even better. Additionally I like the game play of it, the randomly generated world means that I never know what is down in the mines guarding those diamonds and I never know from where they're going to attck. And in the end since the method for how I find and obtain those diamonds is only limted by my own imagination (do I rush in and toss some torches killing mobs, or do I mine through another wall and pick them off, or do I just pour lava into the room killng everything...) So to me the gameplay was fresh enough that I'm always having to think about solutions to new problems.
And finally part of my vote is based on the potential of what MC could bring to the industry. I dream that one day I'll get to play a proceedurally generated world and preceedurally generated story, so that the experience is unpredictable and always unique. Exploring the randomly generated worlds that MC creates is a lot of fun to me, now add in randomly generated towns, NPC's, quests, treasures, etc... And you have a fully realized RPG world that lives and breathes, and with mods it's almost a reality.
Taking it one step further, I hope that companies like Bioware look at the reason why MC has become such a sensation and draw that into their designs. I can only imagine the type of game that Bioware or Bethseda could make with their experience, writing, and developer money to a concept like Minecraft.
AAA developers can't innovate in a true sense because of the financial risk that it presents to develop a new concept. Instead they refine and make awesome what someone did before them, heck look at WoW, love it or hate it, it redefined what an MMO is by taking what previous MMO's were and elevated it to a whole new level. Mojang "developed" a new idea or at least a fresh idea that has created an undeniable buzz (love it or hate it). They demonstrated that there is a market for something different and if any AAA developers decide to incorporate what makes MC such a hit into their games, then I ask who is the best developer?
tldr: MC is fun and I feel innovative, that doesn't mean I hate Vavle or Bioware, they are great too, I see potential that MC can make the AAA RPG's of the future even better.