What’s the point if there’s no requirement to store it? What bitcoin noderunner is going to store nonmonetary data having nothing to do with bitcoin, for free? Would you do that? I wouldn’t. No one will store this data.
If all you want is to force nodes to store a commitment to some data, then that’s already been possible for a long time and requires no changes. Just stick a hash into a tweaked taproot key, or in an opreturn. Done.