It's not just the games missed by those injuries, it's how they might affect his game as he gets older. The lack of 3s is a big factor as well. He's your second choice basically, and I don't know if a team with three max guys who are all second choices is a great play.
At least with Hayward, he does pretty much everything a championship team would need their SF to do, and he hasn't had any serious injury problems. If he can't be signed then they could sign people into the space on flexible deals that could be moved later.
Finally, to be honest I just don't like watching Griffin play.