I coulda sworn there was a wiki topic on this, but ive searched and looked myself; no luck. My primary reason for trying to find this is to see just HOW badly doctor sucks unless you get one of the unique skills

The only good reason to get doctors is if you have lots of soldiers.

I've got two Doctors and they remove poison and heal the injured. When they heal up a Survivor it is awesome, but that's only for my raids as I don't have any Survivors in my main army. Neither has any of the Doctor specific skills yet and I don't regret having them at all.

I've got three Soldiers, dunno if that qualifies as "lots".

i've got one doctor, unfortunately he's not exceptionally quick (+25% speed) nor does he gain any significant intiative boosts but either way he's still pretty good at doing his job and helping my team win. (plus he has a pretty good chance at insta-kills from his mos-teck)

doomys
The only good reason to get doctors is if you have lots of soldiers.
or when you have 3 or more Comms for solo missions ^^