The more I re-watch the show I realize a noticeable change between season 1 and the rest. I don't mean in quality either I mean the tone of the show. I found season 1 more light-hearted, less violent than the rest, like the show seemed to get darker and darker as it got on. I think Tony himself was a more reasonable, level-headed character in season 1, and slowly as it developed in later seasons he had a shorter and shorter temper and seemed to be more explosive in his violence.
I guess maybe the writers were kind of testing the waters so to speak early on, I mean if they had shown the stripper getting beaten to death in the first couple of episodes who knows? They may have lost a lot of viewers etc.

I've noticed that too.

Generally speaking, I think the reason is the general trend of things coming to a climax or some kind or another. Same reason why movies like Goodfellas or Casino go that direction. You can't start out with things already going to shit. They start out relatively well and then, over time, even with short term "good times" along the way, the stakes get bigger and bigger and things get more serious.

More specifically speaking, I would attribute the change partially to the absence of a certain writer after the first two seasons - Frank Renzulli. If you look at the writing credits through the series, Renzulli was a major part of Seasons 1 and 2. But not really through the rest.

I've noticed this as well. Infact i usually find season 1 and 2 to be more closer alike, and the rest being darker. My favourite seasons are the first two, where Tony was easier to like. They relatonship between Tony and Livia was the best aspect of the first two seasons. The scenes with Melfi seemed a bit more fresh as well.

My theory, which is similar to IvyLeague, has more to do with the absence of a actor/character. I think the death of Natalie Marchant left the writers in a scramble, and thus come a much darker tone. The characters go through a noticable change in season 3. This is also the season where we got the most "plot holes."

yes the difference is crystal clear. mostly it's what IvyLeague said but the difference is not only that the show got darker but that it started to handle multiple plots/subplots other than the first two seasons when it was Tony vs. Junior and then Tony vs. Richie.

my favorite seasons are 3 and 4 when the show hit its stride. 1 & 2 are more one dimensional and especially in S1 you can see they are still developing their style - it looks like a Goodfellas spinoff.

by the end of S4 - especially after Tony kills Ralph for no good reason - there is an overall sense of impending doom, like everything is closing in. I remember reading somewhere that originally the show was supposed to be 5 seasons long.

I liked the tone of the first seasons more, there was that heavy italian emphasis i.e the food, it showed more of the mob side such as the truck hijacking, associates such as with Brendan.

I agree that I also liked seasons 1 & 2 best.

I do recall reading that at some point, David Chase was appalled at the fact people really liked Tony and the crew so much that he started making the show much darker and the characters much more unlikable. It's mentioned over at another forum that discusses David Chase and the Sopranos.

The actress who played the mother dying may have had big influence on how subsequent seasons went. The interaction between her and Tony was usually comic, after she was gone that element was less present.

Absolutely. Nancy Marchand's death was a major loss to the show.

I prefer series 6 it starts out with the family strong and at peace and towards the soprano-lupertazzi war they loose 3 capos after wards gervasi rats leaving them with two known capos (paulie and larry) along with soldiers dieing here and there along with a one man administration Tony due to Silvio's injury and Bobby's death