What is the puppet master saying when he talks about puppet shows improving the "present age"?
I believe the passage to which you are referring is the one where the puppet master is talking about morality in puppet shows.
In these lines, the puppet master is saying that the importance of puppet shows is to provide moral instruction and that his puppet-sized dramas are realistic to life and provide as much of a moral lesson as major dramas performed onstage, dramas such as Shakespeare's or Marlowe's.
The present day and age was not improved by anything so greatly as it was improved by changing the nature of puppet-shows. These were improved by eliminating the characters of Punch and Joan and all their idle folly. By this elimination, puppet-shows were finally brought to a rational entertainment. The Punch and Joan puppet-shows did very well at making people laugh but they told no moral story for the improvement of young people's minds. Moral improvement of the mind ought to be the principal aim of every puppet-show. Good and instructive lessons can be taught through the means of puppet-shows. My puppet characters are as realistic as life and represent realistic stories. I believe people depart my my puppet-dramas with as much benefit as they depart from major dramas.