As a more serious reply, Cady, no human anatomy hasn't changed significantly, but the human condition and societal conditions have. Japan, even modern Japan, is a somewhat homogenous society. Ours is not. There are a wider variety of physical types and a wider variety of street crimes. Women must train-unarmed!- against physical assault from a larger, stronger person, something that was not typically done in feudal Japan, as just one example.
While there are any number of modern situations that ancient strategy can be applied to, these require some thought and discernment as well,i.e."How would you defend yourself seated on a subway train?Is the train in motion?At rest?Could you use that pole for anything?What should your first action be?"
Modern attire can be just as restrictive, and sometimes as protective as ancient armor, and one must train for this as well. That seiken to the solar plexus that so many karate instructors(and a few jujutsu schools) are fond of will not have much effect against lots of men when they are wearing their winter jackets, and a seionage becomes really difficult in spiked heels.
In anwer to the original question:I think we should train in both ways. We train in the modern way because the age in which we live requires that we reapply these ancient teachings to new surroundings.
We train in the ancient way because it imparts valuable principles that have relevance for modern use, even if the scenario does not, and because they are where the "art" of "martial arts" comes in. Who cares if we are never going to be kneeling on tatami in our daimyo's castle? It's pretty!
Aaron J. Cuffee
As democracy is perfected, the office of president represents, more and more closely, the inner soul of the people. On some great and glorious day the plain folks of the land will reach their heart's desire at last and the White House will be adorned by a downright moron.
- H.L. Mencken