Re: Opinions and thoughts please...
I think you are making some bad assumptions. (sorry to be blunt, it is hard to describe in type). First, about aikido's effectiveness. People are effective (or not), not aikido, it is a training methodology only, not a skill set.
Second, you really don't know what you will do in a real situation. Hopefully all your years of training have helped you develop some good habits that just happen instead of bad ones. If some one pushed me I don't think i'd do a roll unless it was absolutely the last resort. Hopefully my skills have prepared me to see things clearly long before we get to the pushing stage, but if not ok...maybe turn sideways, irmi a little, bend the legs, couple of steps back regain posture and balance.
People in fights usually aren't going to throw you...they want to hurt or kill you...not throw you. So they will probably hit, stab, shoot you more than likely so that kinda does away with the aikido rolls IMHO. If you are not in a "real fight" where someone is really trying to seriously hurt or kill you and it is one of those "bar push around tough guy" senarios...you must question why you are even entertaining it and walk away.
To answer what I think you are asking in your last line...I don't train to be unbalanced, but to be balanced. I always try to be balanced. Sometimes I am not so I practice ways to regain my balance. Normally though I use my body and manuever in ways that may appear to some to be unbalanced, but really I am in control 99% of the time. That is my experiences.
My sensei's and teacher in the past always preach that uke's job is to work with nage and practice balance and posture while being uke for nage. I would never confuse ukemi in which I am working with nage as a real life fighting method/technique.
Sorry this is hard to write about!