Star Trek

Do you think Deanna would've made a good starship captain?

Short answer: no.

Long answer: NOOOOOOO

Well... I halfway kid, but the thing is, from what we see of her, she is very uncertain on the few occasions when she has command. She does step up to the mark rather than entirely falling apart, which goes a little in her favour, but a captain really needs to be more decisive and display a lot more gravitas than Troi.

So long as she dosen't fly the ship.

As a Counselor, her advice is very important.  But, she didn't seem to have the ruthlessness it sometimes takes--perhaps ordering people to their death, on an away-mission or in combat--to be a good starship captain.