Interesting comment considering it is statistically considered one the most successfully commercially designed aircraft.
Aside from the well known rudder issues (pcu) on the "Classics" . . . which is significant, . . . what other weakness(es) are you referring to?
The 737 was designed in 1964-65 and first flew in 1967 - 45 years ago. It wasn’t a bad design, given the design parameters of the time which included the need for performing with a maximum available thrust of about 40,000 lb from its two engines. Lightness was critical and the skin of the 737 was designed using a rather thin aluminum alloy. These were the “classic” 737s and you will find that they have had a long history of fuselage cracks and fatigue failures.
Most dramatic was the Aloha Airlines fuselage “peel back” of 1988.
Some beleive that the fatigue problem was addressed with the introduction of the NG model. There are still incidents of fatigue and skin failure, for example Southwestern Flight 812 on April 1, 2011 which experienced a fuselage skin failure “peel back” and cabin decompression (it was a “classic” model).
As I understand it these problems are surfacing in aircraft that have not reached their design life cycles, and it appears that some aircraft may need to be removed from service early.
There is no question that the 737 is a serviceable aircraft when properly inspected and maintained. There is no question also that Boeing has made a serious effort to deal with the shortcomings of the original design. I have no hesitation flying on a 737, personally.
I am only making the point that every plane has its failings and its strengths, and that the 737 is no different.
The bottom line is that the Sukhoi SJ-100 has little if any thing that derives from the 737. It has a similar shape and planform, as do virtually every aircraft competing in this market space. Form follows function, as they say.
But copying swept wings etc, is a trivial nonsense. Real copying is in the details of construction, and there is simply no evidence that the Russians “ripped off” the 737.
That’s simply crap. And that’s my point.