My Dobe loves lots of other dogs, especially his own Chihuahuas. No matter what they do to him, how grumpy they get on account of his goofiness, (he can pester them sometimes wanting to play and they get ticked) he still never ever retaliates in any way. He is just a marshmellow, tolerant and sooooo sweet natured. (and low man on the totem pole)
He is dog reactive to strange dogs, but not necessarily aggressive. There are lots of dogs he meets who he wants to play with. They're all different. You can't generalize too much, even though there are tendencies in each breed. Dobes can be very dog aggressive, regardless of early socialization. But they're not all. And I suspect the same is true with Rotties. It can be a protection thing going on which makes them tend toward this way. It can be a leash frustration, which I suspect in my own dog a lot of the time.
I think a doberman might be a good choice for you because the only rottweiler I know kept biting me for food and I don't know any dobermans, though
That's more of a lack of training than temperament. Either one of those dogs can be dangerous and ruined if not handled correctly...socialized a lot and good training, kind handling. Heavy handedness has no place in dealing with these dogs.
As far as the goofies go, Lyric can be dead serious in a heartbeat. When it's working time, he goes into that mode. When someone he doesn't know comes up the drive way or knocks on the door, he gets very menacing sounding. He has come between me and a person who came in the house in the middle of the night. The goofiness is reserved for those he loves and knows. Otherwise, he tends toward suspicion of strangers but a healthy suspicion. Once he checks them out for a few seconds, and we're all talking, he really relaxes....always the gentleman. Can you tell I just love this dog? LOL. I must be sooooo obnoxious.