We previously touched on this in the later parts of the thread [RFC] Remove MemRefType element type check? Or add pointer support to ‘std’ dialect? - #10 by _sean_silva
There was some consensus to loosen the restriction. I think we would accept a patch doing that and updating the rationale doc. See @ftynse’s last post in that thread for a bit more ramifications of doing this that you will need to look out for.