It would be great to have a filter exposed for these so they can be easily modified by themes and plugins.

The tailor_do_shakespeare() function is pluggable, but that's only useful for plugins that happen to be loaded before Tailor is, and won't work for themes at all.

As a general rule, I think the pluggable function pattern is really only useful (and stable) for parent/child themes. That is, until the day WordPress finally introduces some kind of plugin dependency management. 😜