The members of the Executive Board are to be appointed for eight years, and that term of office shall not be renewable (Article 109a). By contrast, the Governors of the national central banks, who are to be appointed for at least five years, may be reappointed (Article 14, Protocol on the Statute of the ESCB and the ECB).
The EMI has already proposed that longer terms of office should be chosen. I think it goes without saying that an independent central bank cannot freely choose its own objectives. But the mandate of price stability has to be defined more precisely; an initial consensus has already been achieved.