Simplest, but not optimal. Ideally you'd want to settle on a mean that:

a) Maximizes arable land, b) Minimizes climate-based natural disasters such as hurricanes, and c) Is as near to self-sustaining as possible. That is, the global mean should not lead to significant growing or shrinking of ice caps and glaciers, nor significantly alter carbon uptake by the oceans. While some degree of human control could make up for heterostatic forces, a swing too far in either direction would quickly exceed our ability to compensate.