Dee, Rishi did not really have a love story. He was a casanova... who flirted/slept with pretty much any girl he wanted to..
But what was appealing about Rishi was his immense love for his big brother (whom he called big B, who was the main lead of the soap). But he hated his bhabhi, so he was like Aaliyah trying to make her get out of his Bhai's life.. But he was so convincing with his love for his bro that you would feel for him.
In the end, he does redeem (that's after 600 episodes), marries one of the girls he dated before (she had a child with him too), and takes care of her, her son etc.. but soon dies.. in bro related conflicts... but soap also ended a few episodes after that.
The best part of Rishi was how bindaas he was. He never bent in front of anyone whether he was right or wrong, never gave a damn for what anyone thought of him.. Rare that you would see a villain with such attitude..
And Milind was a rude, grumpy, rustic guy. He hardly smiles, very bitter with his words...He is full of hatred for rich people (because they humiliated him as a kid, and his father was a poor clerk for a rich family).. when he grows up, he focusses for making money, pretty much buys the whole empire that rich family had.. and even marries their daughter out of revenge (his sister was ditched by the girl's bro).hates her (his hate was real and worse than Abhi)..
But the girl is kindness ki dukaan (like Pragya).. and slowly wins over him.. the falling in love was shown quite nicely, with possessiveness, tender emotions, jealousy, separation, angst etc.. were so well done by Shabz for Milind...He confesses at a breaking point...and even after love confession there was a lot of separation angst stuff due to external interventions, false blames and claims... etc..