God sent Jesus in a human form - a form man looked like at THAT time.
HOWEVER, future genetic modifications could (for arguments sake) have man with two brains, four eyes, three legs etc.
Man in the future could look completely different from now, but still be in God's image. If God had decided to send Jesus in 3000AD, he could look different from the one God sent in the bible, but it would still have a soul.
Is this a fair argument? (Just like aliens from another planet could look nothing like us but still have souls). Or they could have their own method of salvation that brings them to God.
In other words, it doesn't matter what man looks like in the future, God would still see him as having a soul and capable of salvation.