Backstay attachment options?

That is a common way of doing it. Nice thing with this is that the chainplate is external as an internal chainplate (inside the hull in the same location) would be quite hard to inspect as there is not likely easy access. Keep in mind the rigging is holding the mast and the stress and strain of the wind against the sails so it is not something you just want to be making changes for esthetic reasons. A mast falling down on your head more than hurts! Another option is to add a split back stay such as this(ignore comment about old chainplate, just an image I stole off the internets):

but you would need to make sure where ever the chain plates are now located are strong enough and have backing plates. Generally making major structural changes is not a good idea unless it is solving a specific problem.