On the same topic there’s now a Synfig Import Labels plugin that allows to import text lines and their respective timings. The plugin can generate keyframes for you, and optionally a few animations of the provided texts or words (appearance, descend, flight, progressive reveal). New effects can be added (rather) easily.
Any contribution is welcome, such as feedback from tests, new effects templates, a GUI in Scribus… other ideas, check out the open issues!
hope this is useful.
Berteh.