I understand your concerns with the non refundable deposits. RCI wants people to book early and also want people to assume the risk of doing so.
Initially deposits were refundable until final payment date. Then RCI started non refundable deposits with suites and then it spread to all cabin catagories. Then to intice people to book non refundable the difference compared to refundable is sometimes eye popping. These days I tend to book much closer to, or within, final payment when my plans are less likely to change.