Thanks! McCoy definitely did seem exaggerated at times--or haunted, one of the two. Istep is actually not that old, at least in terms of the Cardassian lifespan, though like most Cardassians his physical appearance would make him seem younger to a human than he actually is. I would imagine he's in his mid-50s, maybe very early 60s. To a human eye in the 24th century, though, he would look as though he was in his early 40s.
Istep is definitely fearful of being lumped in with "doctors" like Moset. He was also very upset when he realized his order might be taken as being like those Cardassian soldiers who have raped women on worlds they attacked.
He's more controlled, yes...I know he CAN have a temper, though, but I don't think it emerges anywhere near as frequently as McCoy's.
EDIT: Thanks, TLR! I figured a doctor from a fleet where treating other species isn't the norm would really feel the strain. I'm glad you liked the rawer, more unedited aspect to it--I was worried about how that would come off!