Basically, she just wants to be told what class to play. She doesn't care about the story, or the effectiveness or the playstyle. I want a class that she'll enjoy so she keeps playing :P
Not sure why you fear suggesting something with a resource system more complex than a "flat" bar. She's just newbie - she's not dumb (I hope). Explain the basics of Agent resources to her (KEEP ABOVE 60 - as general rule, at least), and I guarantee she'll have tons of fun with Operative thanks to great animations, amazing story and some nice-looking gear.
Would no suggest BH though, because the story there can be pretty crude, unless she's into "boy's stuff" like fistfights, insults and bragging.