Why would that magically improve the quality of those teams? Playing stronger competition in a vacuum doesn't make you better (word to San Marino). Better players, better youth football, better coaching, better FAs... That is what will bridge the gap eventually.
Plus, do you think club football fans would be for the idea of having the likes of England and Germany fly across the world to South Africa or Australia for qualifiers? The likes of Klopp and co hate non-European international football as is
Finally, you'd have to come up with a fair seeding system. The ELO ranking system is too flawed.
I'm not one of those "if it's not broke don't fix it" guys. I just don't see your idea as improving anything.