1. The news media hates a second term -- wants new faces, new stories, new policies; and historically, 2nd terms have generally not been kind to Presidents.
2. Proposal for a single six-year presidential term does not have merit. Without the opportunity to be re-elected, the President has no political capital to spend or acquire and becomees a lame duck from day one. Rather, the 22nd (?) Amendment which bars a third term should be repealed.
The 22nd Amendment appealed would have had us a longer Ronald Reagan and a longer Bill Clinton though. I truly believe both would have been reelected again. One is good and the other not so much. That is my only negative on that issue.