A few things:
It may be more likely to you, but that doesn't mean that's how it goes. Secondly, even if Luke is stronger, you have to remember that all he ever thought about was his father. Leia might have been the opposite, and even then, she had very few visions of her mom.
Secondly, thinking that newborn babies have good vision and remember what they see doesn't make sense at all.
And thinking that she's thinking about her step-mother, or even one of the handmaidens (as some are wont to believe) really sucks a lot more heart and soul out of the scene in ROTJ. Instead of feeling Leia's compassion for her mom, we now see it as her misguided belief that her Force visions have something to do with her real mom, which is in the script - as opposed to the Annotated Screenplays.