GIMP rasterizes a text layer the moment you rotate, scale, flip, or shear it. That means you can't edit the wording anymore. GIMP’s built-in "Recursive Transform" filter doesn't help here either because it's just a GEGL filter effect layered over stale text rather than a true non-destructive transform, and its main job (creating faded trailing copies) makes it the wrong tool for a clean single transform anyway.
GIMP will probably never have real 3D text (that's Blender's job), but when it comes to 2D text transforms and non-destructive text editing GIMP already has a working core for these features. The developer(s) who worked on it just got partway through, then shelved the whole thing...including the parts that were already finished.
If you dig into gimptextlayer-transform.c, you'll find pretty solid implementations for gimp_text_layer_rotate() and gimp_text_layer_flip(). The scale() and transform() functions are sitting there as empty stubs with / TODO / comments, left unfinished. The whole mechanism is wrapped in an #if0 / #endif block inside GimpTextLayer's class initialization, so it’s completely disabled at compile time. The other pieces are sitting right there in gimptextlayout-render.c and in gimptextlayout.c.
This isn't about designing a new system from scratch. It's mostly just about finishing code that GIMP already has. Anyone want to take a crack at it? It's a bit beyond my pay grade.