No, doctors don't suck. In fact, WITHOUT that amputation, TAK's mom would have been even worse off. Since TAK says it's not that big of an issue to him, I feel I can say it openly: WITHOUT that amputation, she'd probably have snuffed it. Leg would have died and started spreading poison all throughout her bloodstream as it decayed. Again, no disrespect intended.
I myself would have bought the farm twice over if it weren't for modern medicine. Yes, doctors make errors and misdiagnoses from time to time, sometimes with disastrous outcomes. EVERYONE makes mistakes, but because of the area they work in, the mistakes that doctors make can have much direr consequences than those of, say, a farmer who accidentally spreads too much fertilizer on his field.
A doctor is not perfect, and we can't expect it from him. If we did, we wouldn't have any of 'em left: back to giving birth to your children at home and hoping that they are among the lucky 25% that reach adulthood. If they get REALLY lucky, they might even live to the ancient age of fity.