SYDNEY, May 7 : The dollar remained on the defensive on Thursday as hopes for a de-escalation in the Iran-U.S. war supported oil-exposed currencies, while Tokyo resumed its verbal intervention in support of the yen keeping speculators cautious. Iran said on Wednesday it was reviewing a U.S. peace proposal that sources indicated would formally end the war but leave unresolved key U.S. demands that Iran suspend its nuclear program and reopen the Strait of Hormuz. Analysts were worried any