In a perverse manner, the more out there you are with large debt and the more the economy falters (provided your tenants don't falter) the more you will benefit by large interest rate cuts. Really high lvr's will hurt you though.
For instance $1m in borrowings on total assets of $1.428m (assuming 70% lvr) with a net rental yield (after all expenses) of 4.5% doesn't look too flash at the moment.
If RBA rates fall to 4.0% and bank interest rates are around 6% these properties will end up cashflow positive.
i.e.
$1.428m x 0.045= $64260 annual net rental income
$1m x 0.06=$60,000 annual interest expense
$4260 cashflow positive
Of course the ability of oyur tenants to pay the rent will always be an issue. You don't want the economy to completely fall off a cliff.
Your spot on with this, and its what many D&G's forget. The market value of your investments may drop, but who really cares if your net cash flow is increasing.