Re: high breakfalls?
In my experience, the ONLY serious physical aikido-waza I have had to use outside of the dojo has been ukemi/breakfall in nature...literally. I have taken a decently high ukemi while mountain biking (I did an end-over my handle-bars); and I have taken a hard ushiro sutemi slipping on an icy staircase. Forget bar fights – Nature gives you enough opportunity to practice Aikido in real life.
On the other hand, I have probably averted having to take ukemi/sutemi in the first place by having relatively more body awareness as I walk through my environment; and this comes from not bailing at the first hint of danger, but instead trying to soak into the openings and counter. Either way, I always tell new students that they are more likely to use their ukemi-waza out in the street than any nage-waza.