If TF Comics will finally be finished, and the authors will reveal TF2 Pyro's true face in Chapter 7, they could add a limited cosmetic item: Long Awaited Disclosure. Equipping it would take off Pyro's mask, revealing their face and changing the voice lines to be fully understandable.

If this will be real, I sincerely hope that Pyro's canonical face would be absolutely not disappointing, unlike the fanarts.