I just bought some 212's aswell and was told a lot of runners wear them without socks. But that was generally, not just specifically the 212.
The main reason being is that your feet will never remain totally dry in any shoe in severe wet and any socks just soak up the water and can make your feet feel uncomfortable and sluggish. Some will fare better when wet (material and ability to drain away water or not rub due to some socks being multi layered and some are not).
That said I've never been bothered by wet socks and would have to try going sockless myself to really gage the benefit or consequence. The 212 are supposed to be a precision fit so am wandering if I should have bought a smaller size and gone without socks too. I found my usual size 10 too big and the 9.5 too small so ended up buying the 10. I'm wandering if I should have gone for the 9.5 and gone sockless.
Tomorrow morning I'm going to cristen them and since they feel a bit long I will be wearing socks.
Another excellent article; on par with the 12 commandments. I was reassured i'm not a crazy one by (often enough on my down hill pursuits) imagining myself as a warewolf hunting down my prey - sometimes being chased by one* (makes you forget about the pain). *Yes an imaginary one. (try not to look behind you too much or you will end up on your face in the mud).
On a more sober note. The 'another 30 seconds and ill be at the top of the hill and the pain is over' tip, is very useful.
My personal experience tells me...go see someone that can check the alignment of your pelvis.
If your pelvis is aligned correctly then it will be a case of one of or all of the following:
The knee has to travel in a straight line otherwise it will get aggravated and cause pain and all of the above can cause the knee to travel out of alignment.
if your pelvis is not aligned correctly then you will not run pain free no matter what you do so that is what I would do first and then you can address the above.
Still having issues myself but since getting my pelvis back in alignment things have become much better.
My answer above is purely based on personal experience and I do not claim that any of the above will work for you. Like myself, you will be aware by now that trying to find an absolute answer to any knee problem is impossible.