While ripple might eventually be a great alternative to bank loans, it is still a debt system. Any debt system could collapse when there is a "run on the bank." With ripple, a run on the bank would happen when everyone decided they wanted to call in all their debts from a large borrower. Only then would you know if there was actually enough BTC currency to back the debt. Chances are the answer would be no; debt systems lend themselves to fractional reserves.
This is my analysis as well, with the exception that I think it would probably work the other way around, with borrowers defaulting and basically the entire system becoming insolvent. Regardless, I expect it to be regulated straight into oblivion, for exactly this reason. Finally, those who have been calling for a regulated crypto-currency will get what they've asked for.