I love Direct Assault (certainly not a rush card, however). But it is good out of Stark too, which makes it hard.
Jeez...I really don't know. I would say King's Hall as the most solid card, and Core Mel as the most bomb card. She isn't as fragile as other 4-costers since if she died you have a plot that brings her right back. KoF is running a close 2nd - he is both a Lord and Knight (and 3 cost) which helps him edge out Robert (which I agree with LoB is really just as good or even better since kneeling doesn't hit him).