Trishul has a better cast than Kaala Patthar, but IMO the latter is the better film. Yes, Trishul has Sanjeev and when did he ever fail to satisfy? But his character is most undeveloped in my opinion. In the beginning it is clear that he loves Waheeda, is forced by his mother to marry the rich man's daughter, is torn when she announces she is expecting his child - so he is not all bad. But would just that one act of weak caving-in make him more and more extreme in his dealing with people? No fault at Sanjeev's door, he did a very good job with the material given him. Rakhi was just there, Sachin and his lady, not needed other than to stage a coup against the patriarch. Shashi was quite good, as was Hema - their love story was convincing. Amitabh yet again stole the show with his simmering rage and outrage at the abandonment of his mother. The fight scenes were so real, but the story was somewhat predictable. This one, like Kaala Patthar, was also mostly focused on the story and did not rely on too much romance or songs.
One thing I like about these oldies from Yash Chopra is the very matter-of-fact dealing between the sexes. In Kaala Patthar Shashi invites Parveen to stay with him after she is thrown out, tells her he lives by himself, and without any coyness she accepts. In Deewar the relationship between Amitabh and Parveen is most matter-of-fact. In Trishul the same goes for the relationship between Waheeda and Sanjeev. And these were educated people, not from the lower strata - yet they did not have the prudishness one sees on display in modern fare.