My issue with Traviss is down to her as a writer and has nothing to do with her temper tantrums and inability to respond to criticisim.
She has a consistent running theme in her books that all Force users, be they Jedi, Sith or whatever else are inherently bad and dangerous and untrustworthy. This is something that is constantly hammered on the reader with characters taking whatever opportunities they can to parrot these opinions. In a couple of cases where there have been former Jedi in her novels, they have to talk about how horrible it was to be a Jedi and how they're so much massively better off now that they're doing something else.
At the same time, the Mandalorians are constantly being held up as not only the best at everything in the universe, but also morally superior to everyone else. Despite the fact that they're an aggressive mercenary culture with a history full of things like planetary bombardments and attempted genocides, Traviss has to point out how much better they are and how they allways hold the moral high ground because of who they are. Her Mandalorians are vomitously pure paragons of good that are held up as a standard that everyone else should aspire to. And even if it's not stated outright in text, it's a clear message that she's trying to get across.
Added to this, as said, she felt the need to constantly harp on about how the Mandalorians are better then everyone because they are. Thier armour is the best armour in the universe. They can defeat anyone else in a fight. They have the best spaceships. Their society is entirely without flaws or blemishes and everyone is allways equal and everything else. And all this is often done when it has no relevance to the plot. Her trio of Legacy of the Force novels were mostly full of Boba Fett extolling the virtues of all things Mandalorian while the actual plot elements ("Some Jedi called Maria Jade or something is killed. Who cares, she's jsut a Jedi") are afterthoughts.
Another good example would be in the penultimate book of the aforesaid series. Boba Fett's training of Jaina Solo consisted of him verbally abusing her at every step and denegrating everything she had ever done in her life. And then, because Travis was writing said book, Jaina agreed at every step.
That Travis turned out to also be batcrap insane wasn't what makes her an awful writer. It's just the icing on the cake.