Wrong. Obviously you haven't played all the TES games. Only 3 of the games have started out as a prisoner. Arena and Oblivion had the same start area, inside the Imperial prison and Morrowind you were on a boat. Being a prisoner allows you to be able to start off fresh without anyone knowing you without having you wonder how you got in the prison in the first place. It's not moronic or unoriginal. It is unique to TES as it's tradition. It's not idiotic, it's a perfect formula for TES game beginnings just like the perfect formula for Star Wars is "A long, long time ago in a galaxy far, far away" because the star wars beginning allows for them to mold the story the way they wish to without having issues of preconceptions getting in the way. The same goes for being a prisoner. It isn't sure who you were or why your in jail since it only matter who you will BECOME. If you know that what you were before you started the game then your inclined to RP in response to the backstory of the character instead of to your own liking. That makes for a less enthralling RPG.
That explanation is thinner than English breakfast tea.
For a game that sells itself EXACTLY on the promise of no walls, no limits, and a complete player-controlled environment and game progress, it makes very little sense to start in prison, unless you like to call it 'tradition' because you can't come up with something better. Tradition doesn't mean it's good, it just means that it's tradition.
Since the game is designed to let us control our own fate and decide our own path of progress by letting us go wherever we want to and do whatever quests we like, it would make a whole lot more sense to start us out as a free individual under circumstances decided by ourselves during character creation. We're just going to do whatever we like anyway as soon as we get out of prison. People on these boards are describing games where they have roamed around for hundreds of hours and made it to level 20-something without even starting the main quest. Some play heartless assassins, hardly the empire-saving persons we're supposed to be, but the game lets us play those characters because it's so much more than a main quest story line.
With this new AI, as i understand it, NPCs become much more interactive and can approach you in the streets. That would be a much better way for me to be introduced to the main quest line than a psychic Emperor magically appearing in my prison cell and naming me the savior of the world. If I was trotting along, minding my own business, and then heard rumors in the streets, at an inn, from a bard I met on the road or some such event, I could decide for myself if I wanted to get involved in the main quest or not. Instead, in Oblivion, I'm left with a sense of urgency and a bad conscience for not doing like my Emperor told me to, cause I'm that kind of person. Not cool.
This game is about the free choice, so set us up like that instead of clinging to a poor idea because of some vague tradition.
Just my 5C.