As much as I like Hayward Griffin is my choice.
We would get Griffin during his age 28, 29, 30, and 31 seasons. Even if he has some drop off in athleticism it shouldn't be that much. He has enough of a diversified game to deal with some decline in athleticism.
Griffin is capable of truly monster games which matters more in the playoffs than in the regular season. So what if he doesn't play 70ish games or so during the regular season as long as he is healthy for the playoffs. We are a pretty deep team, deeper than the Clippers that we can withstand him missing games.
If we sign Hayward it would mean we would have to make another trade for a PF, as we can only have so many SG/SF types on the team with a gaping hole at PF. It's easy to say trade for a PF but who would that be? There has to be one that is available and worthwhile for us.