I would agree with the idea that the founding fathers' opinions trump anyone else's when it comes to questions on the original intent of the constitution. After all, they wrote it, and they would know better than anyone what their original intent was. I'm not arguing that.
What I'm saying, is that when the question is how should we interpret and apply the constitution to the world we live in today, the opinions of the founding fathers count for less. Their opinions on it are not without merit even in such a discussion, since they were intelligent men, and the original intent of the document gives us a jumping off point, but this is mitigated by the fact that when they wrote those opinions, the country was a VERY different place. Societal values were different, the physical makeup of our country was different, and the difficulty of communication made for a very different political and social landscape in America.
Change just for the sake of change is bad, but so is tradition just for the sake of tradition. Just because the founding fathers interpreted the constitution in a certain way is not a good reason for us to do the same. If we are to follow their interpretation, it should be because that manner of interpretation is what is best for us in the world we live in today.