That's pretty much what I said I was planning to do (except for me, the tipping point was one higher...1-2 loans for 1 interest, 3-4 loans for 2, 5-6 for 3 etc.). I haven't tried it yet, though. It will definitely change the feel of the game, but I don't know if that's necessarily bad.
EDIT: If you are going to do this, I highly suggest implementing an additional rule that you can't take extra loans to pay interest on existing loans. In that case, players would have to liquidate their assets (buildings etc.) first. Otherwise, I can see this spiraling out of control.
EDIT: If you are going to do this, I highly suggest implementing an additional rule that you can't take extra loans to pay interest on existing loans. In that case, players would have to liquidate their assets (buildings etc.) first. Otherwise, I can see this spiraling out of control.