I don't agree that privatization is the answer. That will just add an additional layer of bureacracy, just like the Medicare HMO plans.
The answer is to change it from a guaranteed benefit that is based on your last few years working to a cash value benefit program, that pays out based on a set amortization schedule. Just like the corporate world has already done by abandoning defined benefit pension plans and going to 401k's.
The problem right now is that the system uses current tax receipts to pay beneficiaries, instead of invested funds. That's got to be stopped, because everytime the ratio of workers to beneficiaries changes people are going to be scared the system will bankrupt.
If by privatization you mean the investment into riskier investments that pay a higher return than Treasuries, I'm against that. Yes the return could be higher, but who is going to bail out the people who lose their funds? They would fall back onto the government's shoulders.