If you are rerolling, might as well reroll till black. Or Sherry, if you are not planning to spend.
For blacks, anyone (but Liana, she is a bit too expensive to field for a new account) will be good, but extra good ones are, in no particular order, Sybilla (because rune fencer princess), Nanaly (because dat quad shoot), Minerva (quickshoot ranged assassination with ridiculous attack power), Mikoto (because za warudo!), Despara (because that witch hurts!), Deine (because she is a stone wall that crushes anyone who dares to oppose her) and Aisha (because Aisha. She is that ridiculous).
Platinums you might want to consider are aforementioned Sherry, Gellius (the adamantine wall) and Jerome (best UP generator).