It just kind of seems like if they were made treadle or hand crank they should stay that way, just a feeling I have. Not to say I wouldn't change one if I wanted to, just my feeling is it is like cheating them or something.lol There are so many electric's available today, I just don't see why I would change an oldie to electric if it wasn't done already.
Other than my feeling go with what you want to do, it is your machine and you know what your needs are.