Trigger Areas/Entities, Normals, and Decals
Just 3 wishes: it would be nice to be able to tie programming between game engine and Blender in a way that you can define triggers in your game engine of choice, and you can simply shape the triggers in Blender, and they'll just work. Something like this has been done before, in Folded Paper Engine, which is an addon for Godot and Blender, but it's far too rigid as far as I've seen. Same for entities, too
Next up, I'd like to be able to make Valve quality levels, and the 2 things I've noticed make a detailed map in Valve games since HL2, aside from the props, are the normals and decals. It would be nice to be able to set up normals for each texture, being able to edit them independently from the albedo.
I know that Blender can do decals, it's just that it's impossible to import them to game engines without baking them into the texture, which is just inconvenient. Maybe making the decals a separate mesh from the currently selected model would be a good idea?
Out of these 3, I really only expect the normals to be possible, but I do hope you're able to do the rest.
Triggers is definitely possible. I won't include it in Anvil directly because you need to have something on the game engine side doing that translation, but it's totally possible for you to, in Godot for example, write a post import script that checks for meshes with a certain naming scheme and turning them into triggers
Setting up normals is already possible in Anvil sort of. You can edit the materials Anvil generates manually in the blender shader editor, and I believe gltf will detect when you use a normal texture. Anvil may have a better UI in the future!
Decals as a separate mesh face is very interesting and I don't see why it shouldn't be possible. Consider it on the to-do list!
i found some paid addons that do the 2 things that i wanted.
https://superhivemarket.com/products/nexus-godot-pipeline
https://superhivemarket.com/products/decal-flow