I'm not really concerned about this, no. Ren'Py's developers value backwards compatibility, so it's unlikely we're going to lose functionality. If some parts need tweaking following the change, I'll simply make an update to the tool, and you would be able to continue using this initial version on any earlier Ren'Py engine releases. In general I try to avoid modifying engine internals wherever possible, and if I do (often to fix bugs) I always ensure that if I need to change how the tool accesses that part, your "front-end" code using my tool won't have to change. So, I wouldn't be worried about it.