My only feedback is that I would like an ability to completely disable the feature for myself. It's almost there but I'm missing some way to remove character portrait from PvP intro. Just give us some neutral plate in its place and I'll be happy. Or an option to save a portrait with no character visible.

And unless such option is provided I'm generally against expanding the use of plates to post-dungeon screens and so on.
I noticed while creating mine if you zoom all the way in on your character and use an emote that makes them lean in, it clips the camera into your character and makes them disappear. This could work for you.
The other option would have been to not make one I guess but I don't think you can back out of the feature once you have edited a plate.