Has Toyota fixed traction control issue older Prius had?

Our 2011 Prius is not good on slippery winter roads. When the wheels start to slip, the Traction Control shuts off power to the wheels. So you can't pull the car up a slippery hill as you normally would: allowing some slippage but still making  progress. All progress just stops. If I'm stopped on a slippery hill, it may be impossible to move forward at all. Wheel immediately start to slip, and power to wheels shuts off. I need to back down the hill and get a running start.

At those times, I feel like I'm on Ice Road Truckers, driving in Alaska in winter.

Still, we are considering a newer Prius. Has Toyota fixed or mitigated this issue? I've tried researching it, and some places say later models are better, but I'm not finding the full story. I'm hoping someone here really knows and can give me the straight dope.