My personal choice from day 1 would have been Sneha Wagh for this role. She conveys the soft gentle image that Rukmini is supposed to have, and would also show the emotions of losing her baby really well when Pradhyumna is kidnapped. But Pradhyumna is the only part really left for Rukmini.
No point in giving wish lists remember for casting what happened to satybhama's castingđ