Very well said!
Mother's love for her child is/should be selfless. That is, if something is appropriate to do for the betterment of her child, she will do it even if it causes her pain. Her job is to give the child as he/she grows confidence to make choices, make mistakes, and guide to correct those mistakes. As a mother I would guard my child's interest first ( that's where a mother can get a bit selfish) provided it doesn't cause harm to others.
Ishwari did none of these. She is selfish to the core. She wants Dev to smile only if she is the reason for it. As soon as anyone else is the source of that happiness, she cannot stand it. He has to be everything only what she wants him to be. And he was that way until he met sonakshi. That's the only time he wished her for himself otherwise all other wishes were ishwari's wishes which he kept fulfilling.
RR's love for her son is selfish... she only means his happiness. Everything she does is for his happiness whether or not she is exactly happy with it but she accepts everything ( right/wrong) if that is what makes him happy.
You can say she is a better mother of the two. Or may be you can say that she at least has some qualities that makes a mother but ishwari is an epic failure.