The only thing that is possibly op about physical is arrow storm, which a magic party would have 3 magic versions of it.
However when I fought the gods mates in hall of echos they had 100% immunity to all magic. Fane had to use a hammer he was ill equipped to use as every point was in INT.
Sure there is evasion and that is a bore for physical dealers.
After 150 hours playing 2 lone wolf (one archer, Lohse, one inquisitor, Fane) sure they don't mesh but I only just got to Arx.
I can't see 100% either Physical or Magical would work. One or the other has to sit out a fight occasionally as they have nothing to add. If your enemy has evasion or 100% immunity you are stuck - you MUST use other trait.
That's a good thing though innit? Alive and dead, magic and physical, male and Lohse,