I
still say having auto mode at the end will result in a really crumby game.
And although I LOVE the idea of using frisbees, I'm not sure if the game you describe would work. One of the simplest ways to play it: do what you can in regular mode, and as auto mode draws near, position yourself in front of the opponent's goal, activate a pair of sails or a net of some sort, then wait for your sit-still-and-be-blocking-the-goal-for-thirty-seconds auto program to kick in.
Also, for all the people who want a frisbee game, I love frisbee. However, from playing with frisbee's all the time, to make a robot that tosses frisbees well is VERY complicated. Not only would you have to develop a mechanism that adds spin to the frisbee, you'd have to develop a mechanism that can release the frisbee (WHILE adding spin to it at the same time) and a mechanism to reload the frisbee launcher, possibly with frisbees from the ground. The point is, if FIRST did decide to use frisbees, maybe one or two teams would make a frisbee launcher. For the rest, like the stacking this year, it just wouldn't be worth it and they'd build box-on-wheels plowing bots or bots that would block the goal.
Point is, in my opion, a game designed for frisbees will be just as anti-climatic as this year's game way - it's not going to be played the way the game creators wanted it to be played. Frisbees and ultimate will just have to be left to the people who play it outside during lunchtime.