As my pronunciation is quite impeccable, I am not part of that group, though I can still see the usefulness of such a feature. But, as Mike will also tell you, you have to be aware that there are hundreds of feature requests on the To-Do list, among them many good ones, and a single programmer who also has to keep the current app compatible with the newest iOS/Android releases at the same time. (According to Mike, that alone takes a couple of months off each year.)
I recommend that you get creative in the meantime. Why not take any Chinese text of your proficiency level and try to dictate the whole thing into your device? That way, you will also quickly see what is understood by the engine and what isn't.
Also, if you have good recordings of all Chinese syllables in different tones from language textbooks, repeating these until you see an improvement is basically the most effective thing you can do. If you like, I can recommend which textbook's recordings I used a long time ago.