It is charming. I know some say the EMH was overstepping doctor/patient boundaries but everyone on the ship is his patient. He's attracted to 7 because she has similar struggles to himself, understanding and claiming humanity (oh so star trek, LOL).
I'm not sure having similar struggles works out well, probably most times it does not. You either end up feeding each others dysfunctions or as would happen in the case of the Doctor and 7 one person moves past the particular psychological drama that bound you together and the relationship no longer works.
All of which is more interesting than the way they ended 7/C in the books, just kind of wandered away without a whimper if I recall correctly. Rather realistic but dull. Better for 7 though to have her starter husband to practice on. A relationship with the doctor would have been entertainingly adversarial for the viewer but not good for 7 herself.