Ishmael; Wild or Great? God doesn’t know again.

17:20 says, “And as for Ishmael, I have heard thee: Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly; twelve princes shall he beget, and I will make him a great nation.”  This would be good and fine but Gen 16:12 says, “And he will be a wild man; his hand will be against every man, and every man's hand against him; and he shall dwell in the presence of all his brethren.”  Which is it?  I guess Omniscient god didn’t know again.