Acot, I disagree.
I'm new at this myself, and I'm no Japanese historian, but from what I've read, Samurai, as well as the Japanese in general at the time, devoted much of their attention and time into perfecting whatever it is that they did. So, if their place was that of a warrior, it was their duty to perfect their skills. In order to do this, they would have had to adopt techniques to serve them. It is true that the techniques would have had to be adapted to a more intense situation, such as battle, but I highly doubt they abandoned technique, especially at a time so critical as close quarter combat.
As far as myself bringing it into a street or barfight, I might try and apply the techniques depending on the situation (and the attacker
), but may have to resort to punches and kicks due to my lack of expertise. I would hope that a more experienced aikidoka would be able to hold their ground in a fight (not necessarily by beating the crap out of the attacker, but by putting the attack down without running away).
To answer the question at hand--I do believe that the nature of fighting has changed between feudal Japan and modern North America (that's the comparison here, right??). People tend to avoid killing each other this day and age, since the legal grounds for killing your opponents are far less diverse than in feudal Japan. Without the pressures of family honor and the other guy's katana, I'm sure most reasonable people would back down before things went too far. I'm positive that when properly applied, aikido would be as effective as aikijutsu was back then, or as effective as any other martial art is today. It may even be safe to say that ideal aikido (with the central principle of not actually harming your opponent) would be one of the best applied martial arts in a barfight or streetfight. Not only are you defending from your opponent, but you won't get nailed to the wall by the cops for killing or seriously maiming your opponent, unless it happens by accident (I hear it happens to the odd martial artist)...assuming you follow the principles of aikido, that is.