I'm beginning to laugh at the distinctions people draw between "good" and "bad" Dario Argento films. They all seem to have some common technical elements: clever camera-work, grotesque but deliberately unrealistic violence, weird music, incomprehensible plots, "impressionistic" titles, and poor acting. None of them work perfectly, even for fans of this style. The variations between the movies, then, come from the genre accidentals "Profondo Rosso" is a detective thriller, "Suspiria" an occult conspiracy tale, etc.; Argento seems to come along and apply his own unique vision of the giallo onto whatever horror style is fashionable at the time. It's his uniqueness, rather than his ability to produce great films, that has assured his place in the canon.
So, then, "Trauma" turns out to be exactly what we would expect from an early nineties Dario Argento film. Camera-work? Check even in this late period, Argento's eye and technique are strange and impressive. Violence? Double check although what the actual purpose of that Decapitron device is supposed to be, I can't imagine. Weird music? Check orchestral rather than Goblin this time, but still louder and a little more engaged than we would expect. Odd plot, check, arbitrary title, check, bad acting, check Asia Argento actually manages to make Aura a likable character, but you can't deny that she garbles her lines and seems mostly amateurish throughout. (And she's hardly alone in those respects.)
The slasher subgenre had died out a bit by this point, but no better reason for Argento to try to freshen it up a bit with his unique stamp. The story's quite watchable and fun, and occasionally funny too - more in the vein of "Phenomena" than the early stuff. It's frequently ridiculous, of course, but show me a movie of his that isn't. And while there's a sex element to the film, it has a surprisingly innocent quality, perhaps because Argento was directing his own daughter in the lead. (I'm sure Freud would have a field day with it, though.)
In the end, it's hard to strongly recommend it to anyone diehards are as likely to hate it as love it, and casual viewers are going to find his style absurd. So I'll give it a 6.5, with the simple comment that I would watch it again.