You asked about the weaknesses of the F and F2
You asked about the weaknesses of the F and F2
Sover Wong overhauled my Nikon F and F2 x 2.
Weaknesses on the F:
The F prism is padded by foam which decays and pulls the silver off. It is hard to find a Nikon F prism which doesn't suffer from desilvering. If you do have such an intact prism, then send it to Sover right away to get the foam off. I've had North American repairers (including some well known names) claim that they took the foam off, but Sover proved to me that they didn't (by his photographs that he takes as he is dismantling).
Also, the decaying foam is a fungus growth medium. Especially if your camera lived in humid Japan, Hawaii, or Florida, expect a lot of internal fungus.
F2: the shutter needs to be carefully treated. Nikon's manual said not to keep the shutter wound for a prolonged period of time, and Sover confirms it. If you want to keep the shutter accurate, only wind before you are going to shoot. The F2 allows continuously variable shutter speeds between 1/80 to 1/2000. The F only allows the shutter speeds on the detents.
Meter heads for F and F2 - the carbon resistors of the early F meters and F2 Photomic prisms wear out. They can be rehabbed to some extent. The sturdiest meter is actually the F2A, which has a wire-wound resistor. It will last several human life times.
In my continuous search for an FTN prism that wasn't desilvered, I found a mint looking one from Japan. Sover noted that this particular FTN was very late production, actually 5 years after the F officially ceased production. Also, the FTN was the only one of its kind that he's ever seen with a wire-wound rheostat, like the F2A. Alas, there was internal fungus (see note above about cameras from Japan). Sover has sterilized all of my cameras to rid them of internal fungus.
Oh, the CdS cells of the F and F2 meters may die. Sover has custom made replacement CdS cells!
Also, the F and F2 use a lot of internal foam seals. Most repairers leave them rotted. Sover replaces them ALL. The rotten foam is why my cameras were gowth chambers for fungus.
The F2 MD-3 motor drives have a problem with an idler gear made of nylon. The nylon inevitably splits with the strain, and the motor becomes useless. I picked up a mint MD-3 with this problem.
Sover makes a BRASS replacement gear. Now this motor drive can really power through a roll of film. However, compared to the F3's MD-4, the F2 motors are rather more crude and mechanical in nature.
Finally, in spite all that you read on the net about these cameras being able to "pound nails", they can't. Their plates are thin brass with chrome or paint. These panels are easily bent. Here, the Leica plates are much heavier brass, and far more rigid. However, I wouldn't use an M7 to drive nails. Neither should you!