What problem does this solve or what need does it fill?

Triangle strip meshes require PrimitiveState::strip_index_format to be set for primitive restart to work. The current implementation of StandardMaterialdoesn't do this.

What solution would you like?

Add an extra field to StandardMaterial of type Option<IndexFormat> the value of which will be assigned to RenderPipelineDescriptor.primitive.strip_index_format in Material::specialize
OR
Add an extra field to StandardMaterial of type PrimitiveState (and remove redundancies this creates) the value of which will be assigned to RenderPipelineDescriptor.primitive in Material::specialize
OR
Just unconditionally set RenderPipelineDescriptor.primitive.strip_index_format = Some(IndexFormat::Uint32) in Material::specialize, this is less flexible but literally 1 line of code.

What alternative(s) have you considered?

This can already be achieved with a MaterialExtension:

#[derive(Copy, Clone, Hash, Eq, PartialEq)]
pub struct OverridePrimitiveKey(PrimitiveState);
impl From<&OverridePrimitive> for OverridePrimitiveKey {
    fn from(value: &OverridePrimitive) -> Self {
        Self(value.primitive)
    }
}

#[derive(Clone, Asset, TypePath, AsBindGroup)]
#[bind_group_data(OverridePrimitiveKey)]
pub struct OverridePrimitive {
    pub primitive: PrimitiveState,
}

impl MaterialExtension for OverridePrimitive {
    fn specialize(
        _pipeline: &MaterialExtensionPipeline,
        descriptor: &mut RenderPipelineDescriptor,
        _layout: &MeshVertexBufferLayoutRef,
        key: MaterialExtensionKey<Self>,
    ) -> Result<(), SpecializedMeshPipelineError> {
        descriptor.primitive = key.bind_group_data.0;
        Ok(())
    }
}