I don't think it would be a good idea to add fine grained platform restrictions before we even have a way to do this in a coarse grained way at the package level.
During the review of SE-0236, we couldn't come up with a design for coarse grained restrictions that was generally accepted. In my mind, we should revisit that first and come up with a design for restrictions at the package-level that makes sense. Once we have that, we can think about whether it could be beneficial to have a per-target configuration that uses the same semantics.