Well, he does make a lot of mistakes, but I think people are very hard on him simply because of the rep he earned in Arizona and then following John Elway (Griese didn't count). We need to remember this was his first full season on Denver, he was hurt last year for three games. I think it will take him a little while to actually get to the point where sub consciously he knows he doesn't have to make every play and its ok to throw the ball away or take a sack. Brian Griese in his Pro Bowl year here obviously didn't produce as much as Plummer, and I think in time, maybe next year he will feel comfortable and be the great Qb I think he can be.
Another point I would like to make is the fact that at least half those picks were not his fault. The four in SD as I said were bullshit, I know there was one against Atlanta, and I can't think the the few others right now, but even lets say take the four away from SD and the one from Atlanta, I think we would be talking Pro Bowl right now considering he is number 4 in the league in passing, and if not Pro Bowl we would be talking about the potential for many pro bowl years in the future. Honestly, there are worse problems to have as a QB then bad decision making skills. Those can at least be fixed, and once they are fixed, and Shanahan has a history of being great with QB's, I think Plummer could be a top 5 QB in the league.