I'm still not getting where people are saying she's an overbearing psycho.
The fact is, she's worried about her friend, and for a good reason. He's a 14 year old who's trying to fight a threat that know has trashed three colonies and crushed people twice his age without so much as a second thought. The only thing Flit has going for him in this fight is the fact he has a better weapon.
I'd be more concerned if she WASN'T worried about him. Also, people tend to forget she does stop trying to make him leave the ship after a while. Hell, near the end, she's supportive of the whole effort. She could have just as easily stayed quiet and let the crew turn against Grodek. Would have thrown a wrench into Flit's plans pretty easily. Only she didn't. She accepted he was going to do this and so she threw herself into supporting the cause.
As for why we don't see her supporting Flit more directly, take that up with the director. By the end, there's little to no downtime for Flit to actually get any support. Will not be surprised if the novels try and fix that as well. At the end, we do see her trying to help him, but at that point he's still in full blown "Some day, I will be the most powerful Jedi ever! I'll even be able to stop people from dying!" mode. At that point, she's pretty limited in what she can do for him.
Hell, remember what she was doing while Flit was off having his happy montage? Helping the ship, which in turn helps Flit.
Does this really sound like a Machiavellian controlling she-harpy?