Why the 4th season of tv series "Weeds" is total crap compared to the amazing 1-3rd seasons? Different writer? Is 5th season any good?

No, it's the same writer (Jenji Kohan). The series "jumped the shark" in the sense that it ran through its original story concept and had to make a major change to create a new story. That new story is rather darker than the first couple of seasons.(The third season was also considerably darker than the previous ones.) The fifth season is getting mixed reviews.

Some people don't like the new darker direction; others find that the fifth season is picking up some of the wit that they missed in the fourth.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.