So for me there are weaknesses in some views - these are reasons why I do not agree with them, based on my view of the evidence. You do not have to agree with me and I might be wrong. I would certainly not want anyone not to make their own choices.
BuddhismBuddha thought that organised religion was bad and that people should find their own way. He did not want his teachings written down. He saw lots of suffering in the world and didn't like the idea of reincarnation - he wanted to escape the physical and find the perfect Nirvana. To me this is an overly personal thing - you try to save yourself and so the focus is on you and not so much on what you do in the world. So I think that is wrong you need to do the most you can with your life with regard to others, the communities you belong to and to your society.
IslamMohammed began in a very moderate and conciliatory way with the commune in Medina and with the early attempts to unit the tribes. The problem was politics and wars and people changing sides. In the end he gave up and became much more militaristic although the conquests were often tolerant of religions in the countries they occupied. So the problem he could not solve was politics and the problems of people using his example for their own personal gain.
ChristianityNow Jesus wanted people to be more community minded and he also wanted people to find their own ways - this church will not be built of bricks but of people. So he was in a sense a humanist but he was also ridiculously naive and he had some of the worst kinds of people as his disciples. People like Simon-Peter and later Paul were abominations to what he wanted to achieve. The creation of the Christian Churches and their intolerance has been one of the worst disasters of history. He forgot to stress he did not want blind followers and sycophants, and it was all hijacked by Rome to mix religion and Imperial power.
So they all had good intentions but they all made a complete mess, not because of their teachings but because of the way others have used them for their own gains. I do not believe that people are fundamentally bad in a Hobbesian way. I am much closer to Rousseau in thinking we can achieve great things - we just haven't got as far as I would like.