Giving her a personality will let people more genuinely like her character, as well as adding more scenarios to inspire art. Seeing as now she's a blank slate, so it gives little to work with. (Not that that's stopped anyone.)

As far being a bad character, Insomniac has a good track record at characterization. And seeing as it seems like she'll be a prominent character, it means they'll want to put some effort into having the players like her in some way.

Worst case scenario is they go the "strong female character" route and have her be the most competent, badass and strongest (and boring) character to ever exist while making Ratchet a bumbling dipshit to prop her up. But I'd have higher hopes that Insomniac wouldn't do something so cliche and basic.