The spread does and does not work depending on who you are playing. If you have guys that can play man to man in the back end then it gets tougher for the O without making the mistakes.
Teams adjust just like teams adjusted to Florida in the SEC.
Well, that's a problem for any type of offense you run. At the end of the day, if the SEC had to face a spread every weekend then it would be much easier to handle.
Oregon is another example, imagine how much Auburn and LSU would have shut them down if the SEC faced that every week? Oregon is no better then any other team in the Pac-12, they just an offense most teams are not ready for and the Pac-12 does not have the same DL that are in the SEC.