with TPTP plate:

Without TPTP plate, or setting TPTP to use blizzard for neutral mobs:

Anyone knows how to have TPTP show this bar too? if it can not, i would like to report it as a feature enhancement request.

That bar is currently not supported in Threat Plates. There have been requests to add it, see #149, but as there are only very few mobs in BfA, it did not have priority.

This feature is now available in Threat Plates 10.0.x (Widgets - Experience).