It's not as big a deal as you might think to change infield dimensions. The base posts weren't born there, they were installed once the field was laid out. As for moving fences, that's a different story. I wish more balls were put in play, but I also wish there were more scoring chances in soccer.
What age? Not sure. I think 10u/12u should remain at 60'.
Why can't fastpitch allow leading off?