I believe people should be entitled to their social security and all the gains its made through the 40+ years it has been sitting in "safe" accounts. (Safe is in quotes because the money was originally meant to be untouched, guaranteeing it would be there for the individuals, but the government ended up spending a lot of that money and is now using current payments to pay back owed payments to retirees).
However much you contributed and earned in interest, I believe, you should be able to withdraw and use.
I do not agree that there is a cap on how much you can withdraw in retirement. If I earned the money, every dollar in my hypothetical account should be mine to use.
One of the benefits, in my opinion, to social security is that it is a forced savings. If people were left to keep that money that would otherwise go in their pocket, they might buy things they wouldn't have bought and then not be able to support themselves in retirement.
Social Security is a good idea in theory. We have many people in our country that have proven to be financially irresponsible, so giving them no choice but to save - is definitely a thought out approach. As well as creating a way for people to stay financially supported when they can no longer work is a good thing. The ultimate benefit is doing so without further burdening the tax system. (although it might still be burdened but to a lesser extent since there is a pool of pure social security money)
Obviously the current system has flaw, but most large scale complex systems do, especially when the government is involved :p.
These are all purely my opinions, so please think through what I said and feel free to agree or disagree.