About home mortgages and bailouts?

Some say that we should bail out home-owners by buying their troubled mortgages and renegotiating with the homeowner at the lesser value, having the tax payers eat the loss. If we do that, it doesn’t seem quite fair to those that struggled and scrimped and kept their mortgage payment up, and are still paying a mortgage at the inflated value. Would this work? We renegotiate at the lesser value, but put a lien on the house for the amount that we discounted. If the market comes back, and values go up, and the homeowner goes to sell the house they have to pay back the amount that the taxpayers “ate” with the profit. It’s just an idea, I’m not saying I’m sold on it, but I would like to hear pros’s and con’s.